My 92-year old mother, who refuses to see a neurologist but pretty clearly has declined from mild cognitive impairment to something between mild and moderate dementia, believes that she recently spoke to a cousin of hers who "thinks she is a terrible person" because of something that happened literally 75 years ago. I doubt he even knew about it at the time, tbh, but in any case no such recent conversation has taken place and he does not think she is a terrible person... just the opposite, he has warm memories and feels very loving toward her. My mother is miserable and hurt by this imaginary conversation, which she is perseverating on. Is there any way I can persuade her that he does not feel that way about her, and/or that this conversation didn't happen? Could I suggest that perhaps she dreamed it or something? Any suggestions would be helpful, except I'm not going to be able to get her to a neurologist. According to her "there's nothing they can do about it anyway." I'm not sure she's wrong about that.
So we are down to is mom now cared for and watched over 24/7 and in a safe situation or not. Her hallucinations and her imaginings are the least of it. They will come and go and vary. The most of it is now her safety.
If this cousin is no longer alive, I'd opt for a "therapeutic" treatment: ask the cousin's adult child or grandchild to write a short note as if they are this cousin, referencing the incident and making it clear that she holds no ill will towards your Mom. Or you write it. Put it in an envelope and give it to her to read. If she continues to fixate on it, you pull out the letter and have her read it again, then move on to another topic. This is a white lie that hurts or impacts no one, so there is no moral dilemma in this solution.
I wish you success in helping her have peace in her heart!
But what I would worry about is now meeting your mom in her world and quit trying to make her fit into yours.
Your moms brain is now permanently broken and it will only continue to get worse, so there is no convincing her that something didn't happen whether it did or not.
You have to remember that someone with dementia loses their short term memories first and hang on to their long term ones, so the fact that she's remembering something from her past is very normal now, and also very real to her, and nothing you say or do will change that.
Like Lealonnie said below you can try having your cousin talk to her preferably in person as since she's living in the past she more than likely won't put 2 and 2 together that he's the same person who hurt her many years earlier. It's worth a shot anyway.
And to be honest I wouldn't get too stressed over this as in a few days it will be something else that your moms said or done that will keep you on your toes. So just chill and remember that you must now live in your moms world as she can no longer live in yours.
I knew immediatly that was my fault. That she was listening to us talk and now was in a panic that a hurricane was on its way.
I knew better than to do that because about 10 yrs ago aunts neighbor told her about receiving an obscene phone call. Within minutes when aunt retold the story it had happened to her, not the neighbor. No matter what I said she stuck to her version. I decided the best thing was to refuse to discuss it, in hopes she would forget about it. So if she brought it up, I would change the subject and she did quit mentioning it to me. One time when I walked in the room she was about to launch into it with her aide and when she saw me she stopped talking. But every one of her caregivers, even the therapist knew the story…for years, even new people. It was stuck like glue. Perhaps just something she could remember when she wanted to talk.
In both these incidents something was said, just not in the context it was stored by the one with dementia. That may or may not be true for your mom. Dementia is a tangled web.