I live out of state. She is living with someone who just had quadruple bypass and he is not wanting to stay with her much longer. I took her car keys away last time I saw her. She went to see her friend in the hospital, during Covid. Security told her she could not see him. She went to the parking lot and could not find her car. She thinks nothing is wrong. I do not want to anger her as I have access to her bank in the event I need to put her in assisted living. Also have Medical and Financial POA, but I believe I need a letter from a doctor stating she needs help. Correct?
Your profile says your mom has dementia...is this your opinion, or an actual medical diagnosis that would be in her records? If she hasn't yet had an official diagnosis (and even if it's not required by the PoA doc) this needs to happen so she can't block you out of accounts. Right now you need to step gingerly with her and appease her. You probably won't "convince" her of anything going forward -- you must come to understand that the way you interacted with your mother in the past is not how you will be able to work with her from now on. This is hard, and everyone on this forum has walked in those shoes. We get it. My MIL was a very similar story to yours.
IMO you will need to plan to take time off to spend a week at your mom's. You must have your PoA paperwork with you. You will need to make an appointment with her doc to get her a cognitive exam and also test for a UTI, just to discount this problem. Don't wait for your mom to make the appointment -- she will forget! It is ok to employ a "therapeutic fib" to get her to the doctor, like "a new Medicare mandate says everyone must have an annual physical", or whatever it takes. Once there, present a pre-written note discretely to the staff outlining your concerns about her decline and letting them know you are her medical PoA. It is ok to sit behind her during the physical and what (non-cognitive exam) questions the doc asks, you can give correct answers behind her back by your head movements. This is exactly how I did it with my MIL. The docs are happy to accommodate family in this way.
Once this first hurdle is passed, you will need to think carefully about how you will provide her care going forward. I personally do not recommend attempting to have your LO live far from you after this point. This may mean moving her to your home state (but not into your home). Your ability to advocate for her will be greatly improved and your stress reduced (eventually!) If you have any siblings you should discuss what's about to happen with them, even if they aren't PoAs, just so they aren't shocked or suspicious. You will need their help.
Depending upon the severity of her memory loss, she may not be able to be in AL, only MC. You will need to visit the places in person (and not sure your mom needs to be involved in this - she won't remember and she's not making decisions in her own best interests. It will only stress her out). Hopefully you have a complete knowledge of her financial situation so you can plan accordingly. Please know that the vast majority of people who go into facilities eventually need Medicaid to pay for their care. Therefore, a consult with an elder law attorney who specializes in estate planning and Medicaid will be money well spent (and should be paid for by your mom's assets, including any travel expenses on her behalf). Keep receipts to reimburse yourself later. There is much to know so that you don't endanger her ability to qualify for Medicaid, since their "lookback" period can be up to 5 years.
The start of this journey with your mom can feel very overwhelming. This is normal. Eat the elephant one bite at a time. My MIL was not remembering to eat, even though we were 6 miles away and supplying groceries, cooked meals, all types of services. She is now in a facility 3 miles away and doing well. I wish you much success in figuring out the pathway and peace in your heart that there are no "wrong" decisions as this point.