Is there any way to stop POA from being rescinded?

Let's back up to the first part of this. Your mom has dementia? She must be fairly young if her mother is still alive and her sister is still a working dentist. Her mother and sister must be frantic with worry; of course you and your sister are trying to do the best thing for mom, but your aunt and grandmother most likely consider the two of you "kids".

Have you shared the diagnositic workup with your aunt, who has medical training and may be of enormous help to you in navigating understanding what the docs are telling you? I'm going to assume that mom has had extensive neuropsych workups, blood work, brain scans and the like and that all other possible explanations for her behaivors have been ruled out, ie treatable ones like UTI, brain tumor, metabolic/blood sugar problems and the like. I'm going to assume that it's not like her GP said, "oh, your mother has dementia, better get POA".

Unless there are ong standing problems with your Aunt and her relationship with you and your mom (the kind of complete dysfunctionality that makes one walk on eggshells because every single d*mn thing you say gets taken the wrong way) I would share all the information about mom's diagnosis and treatment plan with her sister. If she thinks that more tests should be run, where's the harm in that?

I totally agree that what she did was unethical, but in certain circumstances, it could be understandable. Try to keep the family on the same page. And if I'm totally out of line, I apologize for misunderstanding a situation more complex than was originally written about.

Maybe this is too basic, but the simple answer to your question is "Yes", there is a way to prevent a POA from being rescinded. And that is to demonstrate to either the party seeking to persuade your mother to rescind it, or to the attorney who would draw it up, that she is not legally capable of doing so. Harder to prevent an attorney from doing this, but there are things you can do to protect your mother in case this happens.
The first thing to remember is that a person must be "competent" in order to sign a POA — that includes both the one your mother gave you and your sister and any subsequent one she might make that removes you all and/or names someone else. I assume that your mother signed a POA prior to any medical finding that she was incapable of making medical/legal decisions for herself AND that she has, in fact, been medically tested and diagnosed with dementia. A person with Alzheimer's may or may not be mentally competent to make such a decision — it depends on how far advanced is the disease. However, since Alzheimer's cannot be truly diagnosed except with an autopsy, the convention is for a physician to diagnose "dementia consistent with Alzheimer's" or such terminology, or simply "dementia" unless an MRI etc. shows vascular or frontal lobe or some other sort. However, the issue for competency is the dementia, not the underlying cause for the dementia.
I suggest you ask your mother's physician (hopefully a neurologist rather than a general practitioner/family medicine doc — and better yet if it is a neurologist with definite expertise in diagnosing and treating dementia) if he/she will provide you with a letter stating that in his or her medical opinion your mother is (or has been since at least such and such a date) incapable of making medical/legal decisions for herself. You would need such a medical evaluation/opinion anyway in order to establish a need for guardianship if you go that route. But at this point, you could share this written opinion with your aunt/other family members which MAY help them come to grips with this awful, sad reality. It may or may not persuade them that you and your sisters are appropriate to serve in that capacity, but that is legally irrelevant if that was your mother's decision and they are not prepared to demonstrate that you are presently unfit to so serve. If there is any way for the entire family to be "on the same page" it will save untold heartache and difficulties further down the road.
If that's not possible, such a medical opinion will also put them — and possibly any attorney they seek out — on notice that your mother is not competent to rescind the existing POA. In the face of such an opinion it would be the rare attorney (we would hope not one!) who would permit your mother to sign a new POA. I think that if your aunt/grandmother FAILED TO DISCLOSE the existence of such an opinion to the attorney that attorney would be very unhappy with them bamboozling him and quick to agree that the subsequent POA was no good. The client in this situation is the person signing the POA and NOT the person/persons designated to have the POA. Consequently, the LAWYER'S ETHICAL AND LEGAL DUTY IS TO THE CLIENT — YOUR MOTHER — NOT HER FAMILY. And the client's interests (your mother's) are clearly NOT served by someone who attempts to secure her consent to something she is incapable of consenting to. The attorney must protect HER, not them. And, tho' the lawyer will hate to have been fooled, I can't imagine any attorney arguing that his or her assessment of your mother in his office is superior to that of her attending physician. We all love to beat up on lawyers, but it's also possible that the lawyer won't even be told there IS an existing POA.
I want to add just another note here, SwampRat2 — and this is actually for everyone who posts a question. The people who respond to questions on this forum are very protective and caring of caregivers; all or most of us have ourselves been on or are on the same journey in caring for people with this bloody awful disease and we empathize so much with others in the same boat. We want to support and care for the caregivers who are asking questions and we definitely tend to take the person and the question at face value, believing in the integrity and honesty of the caregiver and, almost by reflex, siding with them "against" the family member, doctor, nursing home administrator, agency or aide who prompts the questioner's complaint. My goodness, some sympathetic souls even suggested you sending Adult Protective Services after your aunt AND accusing her breaking the law. Not true and not called for, especially based on the limited information we have. Notice that you see lots of responders saying, "if you haven't…" or "I assume that..." or "I don't know if…" or "Unless you have...'". We know none of the backstory here. I'm very sure that people who invest the time and concern to respond can be of the most help to questioners who provide quite a lot of information in the first instance or, at least, provide some clarification and additional information along the way. I hope you will do that, SwampRat2. If nothing else, you can "practice" making your case with us as it will be important for you to be able to set out all the facts in support of your position in the event your aunt/grandmother really do challenge your exercising POA. For example, if your mother signed the POA naming you and your sister AFTER she began to be treated for/diagnosed with dementia, you might get considerably different — but nevertheless helpful and supportive — responses. In my own experience dealing with a particular family member is at least as challenging as dealing with my loved one's disease; I really wish you and your sister and all the family success in caring for your Mom and for each other.

Your Aunt broke the law (and she knows it!) and if your Mom's doctor doesn't report her, you should! Your doctor couldn't have provided any info in this instance even without the POA due to confidentiality laws in place, but your aunts actions are a form of attempted identity theft at minimum. And as a practicing member of Dentistry, one wonders if she treats HER patients' confidentiality as the law dictates?! Doesn't seem likely given her actions. Be sure to document this and advise your attorney RIGHT AWAY! They would need to take legal action to rescind the POA. Best to be prepared in the event they do. And your attorney can best advise you on how to report your Aunt for willfully breaking the law and her oath. Your Mom's rights (and potentially the rights of others) need to be protected from "providers" like your Aunt. Best of luck to you and your Mom and shame on your Aunt!

I smell trouble, I had a sibling like that. If your Mom had dementia and the doctor has a copy of the DPOA, you have no problems. They can try and take your Mom to a lawyer to get a new one but is your mom capable of fooling someone that she is okay? In order for a POA to be recinded the lawyer had to say your Mom was not of sound mind when she signed it, duhhh they will never do that, telling someone they were wrong? never! Take good care of your Mom, thats why she chose you. good luck.

I agree with ba8alou. Unless you have solid proof that your aunt and grandmother are trying to usurp your POA for financial gain, I think your aunt may just desperately be trying to find out what is going on with her sister. She has a medical background. Have you shared all of the info with her and grandma? Making decisions for a dementia patient is very tough and taxing. You would do well to get everyone on board and on the same page. It's what is best for your mom. It's what is best for everyone.

Not exactly ferris1. It depends on the kind of POA it is; we don't know that it is a Durable POA. And while I'm not a lawyer either I'm quite sure that one can't give ANY Power of Attorney unless one is mentally capable of doing so. SwampRat2, please understand that what is legal and not legal is really the province of lawyers. The people who reply here are doing so in good faith out of their own understanding and experiences. But laws change, they vary from state to state and one tiny little factual difference can make the difference between "lawful" and "unlawful". Except for the advice above on, hopefully, preventing your aunt/grandmother from persuading/attempting to persuade your Mom to revoke the existing POA and make a new one, you will need to consult with an attorney. I'd start with the one who wrote the POA your mother signed naming you and your sister.

If your mother is established to have dementia, as POA, you can prevent anyone from taking her somewhere without you in attendance or without your permission.

I was in the same position a couple of months ago! My dad & brother had my mom in and out of the hospital & skilled nursing facilities for over 2 years! I broke my back and was unable to help out at the time. Once well enough to walk, I got to her & seen she was in very bad shape. Mentally and physically. She was on many meds making her act crazy and sometimes act out & hit nurses trying to help. The more she seen me, the better she became. She had "clear" moments at times so I took a chance and we visited an attorney. The attorney made it clear that she would not grant me POA unless my mom was in her right mind at the time. Well, she was and I know have it. When my dad & brother found out, they had a fit! I got her home, she is off all of those "crazy meds" & is doing great! She did tell me that my dad & brother tried repeatedly to get her to remind the POA and she totally refused. I took control of her bank account that my dad was dwindling away gambling. (he also has dementia). She has new teeth, getting cataract surgery & a hover round. My dad has come around & all is well. Just takes some family members a little time to see that you are only trying to do the right thing. Good luck & don't worry. Most of the time, they're idle threats.

Yes, Lolli47, I was assuming that mom was competent when she signed the POA in the first place, and I agree to make sure to consult an attorney who is familiar with your state's laws. What a pickle this situation is...

Sandibeach, congrats! Well done!!

GoMelGo, what are you waiting for - file that complaint to the bar association, and get the guardianship. I don't think it is extreme at all, when someone's judgement is that far gone and you have full documentation. You can still respect her choices as fas a reasonably possible after you have it, but she could try and at least temporarily succeed in giving POA to the next lottery scammer that calls if you don't. You seem to have the equivalent of the incapacity letters required for most POAs to be in effect and not revokable unless you fail to perfom the specified duties and act in the best interest of the person, but that did not stop a lawyer who found Mom convincing enough. I think your new lawyer might be ethically and technically correct and competent.

Swamprat, I did not catch it at first, but your phrase "served the POA on the doctor and the bank" is not quite right. Read the document carefully. The doctors and hospital should share medical information with you now, since you have the HIPAA release and medical POA on file, no question; *you now need to ask them for documentation of her incapacity.* The bank may absolutely require that for any significant actions you need to take with her finances without her being present or consenting. My mom's specified two letters; one I got form her PCP, the second from a geriatric psychiatrist I took her to. Given that, I never needed a guardianship, but in your situation it may be the safest thing.