Mom just moved into AL after 2 hospital stays. She has advanced COPD and dementia, She has a recurring fear that my sister and I have placed her in a mental institute and have taken away all of her money. She is calling me and other family members whose phone numbers are stored in her phone 3-4 times daily, sometimes pleasant but mostly angry and yelling. Then hangs up if told it isn't true. Today she told me how much she liked her apartment , new friends and activities. Said she was okay with visiting her home for holidays and weekends. Great. Two hours later I am the evil and she hates me. My sister, nieces and husband cringe when she calls. I visit every Wednesday and my sister visits every Sunday. I can usually cajole her into a good mood or take her out to eat which she loves. This disturbing behavior can happen at any time out of nowhere. Redirecting usually doesn't help. One time I told her I want going to talk about it and walked out of room, came back in a few minutes, acted like nothing happened. Worked that time but not the next So sad that mom thinks I am cheating her and mean to her. Help!
In my dads case for example, with Alzheimer's, he could still read the newspaper even though he could no longer sign his name.
My aunt, with alcohol dementia, couldn't remember how to do anything, pay a bill, fix food, IF she ate, yet she could enjoy going out to eat we're going to a movie (couldn't remember afterward).
My mom with drug-induced dementia, who had been very good at electronics, couldn't any longer operate a phone, the microwave or her VCR.
Still others I have known of (and have read about on this forum) have then incontinent and didn't want to bathe, yet were still able to dial the phone, call for 911 emergencies (when there weren't any) and complain to social services about being abused (although nothing untoward was happening).
This case regarding your mom sounds like it is time do either de-program the numbers from the phone or remove the phone altogether.
It is enough stress just trying to deal with the behavior. Please do not also worry about your loved one dying hating you -- the real person does not hate you, it is the dementia.
Fortunately, my mother's cell phone use it spotty. I send her e-mails at the nursing home. She can't reply, but she gets my news and pictures. I send lots of gifts. It doesn't have to be much. But, I do not want her calling several times a day.
As far as operating a cell phone, it is keeping a list of the numbers that were called and see can just hit the recent numbers. It isn't difficult.
Before they walked out the door, the wife called me to let me know what an evil person I was to do this to my mth! When she finally took a breath, I told her mthr was safely locked up in a memory care home and several states removed from Raleigh NC! I even gave her the number of the home so she could call herself.
Because my narcissistic mthr has always told terrific stories with me as the bad guy, this tale was believable to these people (why they believed any of the stories I have no idea). They called the home and she was there.
I strongly advise allowing your mother's phone to be lost, broken, or dropped in the toilet! Anything to get it not to work. Maybe even take out the battery.