My aunt thinks my mom's dementia is a lie, and isn't properly being taken care of, any advice?

My aunt recently took my mom and my daughter tagged along. While at her home, she got on to my daughter that she wasn't being properly taken care of. That she didn't have dementia, that she simply desperately needed her thyroid pills. So when my daughter asked why she didn't believe that she had dementia, well she said, "Because she is active, and not falling apart like most Alzheimer's patients. Alzheimer's patients are quiet, and basically bed ridden, while some you can't even understand anymore" I was fuming! She has always done this since my father died, and before my mother's diagnosis. she is just the type to meddle. Because my father was no good at taking care of her, and neither am I. Personally, I'm not perfect, I don't claim to be. I have never had to deal with anyone with dementia before, so I play it by ear, and what I don't understand, I ask the doctor, or I look up online. I have gone through the rummaging, I have had to lock cabinets, the fridge, and even had to clean up her room more than once a day because she hoarded things as well. Then she would never recall of doing any of those things. My husband and I have to cook her meals and save portions of it at a time, because she forgets that she eats, and either refuses to eat or wants to eat more. She speaks to people who are not there. But because there are stages that every dementia patient has, and because the disease has not worsened, but stayed the same, and she slowly, very slowly seems to be worsening, it has to be her thyroid. The doctor right before her diagnosis, was called by my husband to inform him that she needed medication because my mother had the flu, and he really didn't want to taker her out in the cold or anything of that nature. He said, "I just want her to rest, and I will go get her medicine" The doctor said she needed to come in, to check her out, before prescribing something for her. He had them set up an appointment, which was a week away. We were reluctant, but he still scheduled it, because the doctor didn't seem too worried. He then said, "You can get her some Robitussin if she starts coughing too badly" My husband was really upset, but because she held the doctor so high in regards to her care, he didn't say anything. Her doctor knew we couldn't give her anything like that, her seriously high blood pressure was not going to help her feel better. So, we did what we could at home, until he could find someone to see her immediately. We didn't find anyone, and she got worse. We took her to another hospital since her, one that her doctor wasn't from, and one that I trusted. There, they found that she had pneumonia. They asked who her Dr was. He told them to NOT do anything until he sent someone from his office to go see her. There he and his colleague could not find the same diagnosis. So he sent her home. I was FURIOUS!!! This is the same Doctor who told me she didn't have anything wrong with her, that she simply needed to take more thyroid, and then when his blood levels would check out, he lowered them again, and they would be normal, and nothing would be wrong, but her memory loss was worse! So, at that moment, when she was sick, I decided to get her a new doctor, I scheduled her an appointment which was for three days later, and sent her to the hospital. I could not go, I was at home with my kids. My husband went, and I told him, "Tell them she no longer has a primary physician, that we are in transition, and the doctor we are looking to be her dr is this dr" so he did just that, they called him, he immediately came to the hospital, signed for her to have antibiotics, and she started to regain her health, that night he called in the neurologist, and that morning she was diagnosed with dementia shortly after meeting the neurologist. He then said, "The illness will NOT be cured, but with medication, and since it's very early, we can slow the disease" He did later put her on both Aricept and Namenda, but he has predicted every symptom, and some I have not seen yet. All three of her doctors tell me, that she has dementia. Even though I was one to try to deny it, or refuse to see it, but the symptoms, and the change of personality, and other things that I have seen, like when she misses even one dose, I know it's dementia. Even though, I hate the disease, and how it has changed her, and how it pains for me to see her get upset, because she forgets how to write her name, I still have to say, that there are things she does, and that I have seen, to prove to me, what I didn't want to see. I'm am emotionally tired with being a mother and trying to keep peace between two teens, and a sometimes hostile mother, who says doesn't need my help. I really don't need my aunt to come bully me on what I am doing wrong, what should I do? I don't even know how to feel. Sometimes, I think, maybe she's right. NO matter what I do, it's never enough.