Music! If she has dementia then Playlist for Life are really helpful, if she doesn't them you can use some of their ideas- talk with her about music she loves, that reminds her of happier times, that was played at her wedding, that she enjoyed when growing up, that reminds her of loved ones, that is in her favourite films, etc, then make a playlist for her.
Same for TV programmes and films, much better to get her favourites rather than the crap on daytime tv.
Other sensory stuff- some people find things like bubble tubes, lava lamps, projector lights etc relaxing. Also fuzzy blanket, silk pillowcase, other things that are nice to touch. Flowers, nice smelling hand cream, maybe something she loved the smell of when she was much younger (I know a few fans of Pears soap as it reminds them of childhood bathtime)
Does she like animals? If she's in a care home they probably have access to Pets as Therapy (the ones around here all have dog visits and some have even had alpacas and Shetland ponies!) If she's at home then some voluntary organisations can take pets to visit people at home- your local social work department should be able to advise.
Do you have children or if not does anyone else in the family have children who might like to go and visit her?
Had a doctor had a look at her sore hands? Might be something that can be done to help, even just regular paracetamol can make a big difference.
Although it's understandable that she would want her life to end when she is so disabled and in pain, I would suggest that she should be assessed for depression by GP- I'm an old age psychiatrist and sometimes see patients who are very unwell and are nearing the end of their lives so it's assumed that their despair and wish to die is due to their circumstances but after some careful questioning it turns out that they have depression and an antidepressant can make their last few months a lot better.