BPD mom showing signs of dementia

My mother has been very difficult all of my life. Her BPD has wrecked nearly every relationship/friendship she’s had and as an adult, I learned to put some very strict boundaries in place. There have been years where she wouldn’t speak to me (we live far apart) and then would come back like nothing had happened. It has been a cycle for 30 years. I have always been the adult in our relationship as she exhibits all the horrible behavior we talk about in this group. I am now 50 and she is in her 70s. The past several months she has been even more confusing on the phone and in text and at first I assumed it was another tactic to elicit pity and attention from me and my family, but after our last few convos, I’m starting to suspect she is developing dementia.

Her second husband seems to be supportive/enabling of her behavior, so I know she has someone watching out for her day to day, but she is growing agitated and confused. She cries constantly and every conversation we have, she verifies my phone number, saying she lost it. She also verifies my bday and those of my husband and daughter every time we talk. She repeats stories in the span of the same conversation. I still have the ability to feel bad for her and now that this behavior has worsened, I’m unsure how to proceed. She is very poor and I have helped her out for many years, so that’s covered, but about her mental health. She tells me she has an appt with a psychiatrist in a couple of months- will they diagnose dementia if that’s the case? How do I put aside my feelings of distrust to help her now that it appears she really needs it? Has anyone gone through this particular thing with their BPD parent? Sorry if this is rambling- I just feel so powerless.

My orange cat pounces at the toy I shake for him, So playful is he.