It’s really difficult when someone is at this advanced age and has entrenched negative behaviour patterns, which sounds like it could be the case with your mum. I think often acceptance (from yourself) is the only way because change/self reflection is unlikely to happen. That’s hard.

One thing. You mentioned her being emotional at others kindness, having no friends. I’m wondering if some kind of social activity aimed at her age group might help? Lunch clubs, or day centres that kind of thing. Maybe meeting others might help focus her mind elsewhere? It sounds like she’s very focused on a small group of people (her family) and wonder if seeing others (even if not making friends) might take her mind elsewhere for a while. Just a thought.