She could be an advocate for people with dementia. My issue with that is people who have dementia can't give full consent. She also has a long history of being exploited. So does she really want to be an advocate? Or is this something that someone close to her has put in her head that this could be her "get out of jail free" card? Is she doing this of her own free will or is she being pressured into it? Like another posters said she also has a history of denial, denial, denial for things in her personal life that were clearly happening.
I'll say from my experience one phone call is not enough to make a sound decision on if she's ok or not. The thing about dementia is there's no rhyme and reason sometimes they can be lucid and acting "normal" and an hour later they can't remember sh!t. It's a reoccurring effect often talked about in my support group. It's small glimmers of who they used too be and it makes you wonder are they just effing with me? Then later in the day the LO snaps out of it and reminds you that they aren't okay at all.
Certain times of the day they can preform better than other times. And there are situations they can "Pass" better than others. For example when I take my dad to church many of the members are aware of his multiple health issues. They'll comment that he doesn't seem that bad. Of course he doesn't seem that bad he attempted to interact with the conversation and participate, he showtimed them. Once we're alone he tells me that he can't remember what they said or didn't understand what they were talking about, what their name was, ect. I'm left to repeat everything over and over as simply as possible. Then when we get home you want to know the first thing he dose? He goes and takes a nap because he is exhausted from the trip to church and coffee hour afterwards. The people who say he's fine only see a small glimpse of him. Now if I say dropped him off at their place for 24-48 hours alone they would have a 100% different opinion on his mental state.
As far as her comments on feeling like she's in prison my dad has also made the same comments. They believe that they can still do things that safely can not do. For example my dad still believes that he's going to get his drivers license and go back to work. He genuinely believes that. What they should be doing is working with her to help curb depression. The loss of function is a major source of depression with people with dementia.