Yep, my MIL always maintained she would never go in a home, but also made no provision whatsoever to keep her body and mind fit and healthy. She was convinced she'd just die in the night!
She did no social activities, had no hobbies, wouldn't engage with computers (not even 20 years ago when she was only in her 50s and was perfectly capable). She didn't even do crosswords or anything like that. She wouldn't go out for, say, walks, never bothered learning to drive, only went out if there was a reason, i.e. to go shopping.
Now in her 80s, her mind has gone (hardly surprising given she did nothing to keep it active and didn't do any kind of exercise to keep blood pumping). All we get is "woe is me!". Well, what the hell did she expect?
It's blatantly obvious she needs to go into a home to be looked after as she's completely incapable of even the basics, but just expects OH or his sister to go round constantly to make her meals, put the bins out, even turn the TV on for her, turn on the heating, do the washing up, etc etc. They both work, so they simply can't spend that kind of time looking after her. But she just can't understand that people work, just because she was a stay at home Mum from the age of 20 and never worked, she thinks that's normal. OH and his sister can get 10-20 phone calls daily from her with some nonsense or other, some crisis (which isn't). But she refuses help, not only going in a home, but also refuses to have carers in the house to look after her. She only wants OH or his sister. She won't even let me in the house if I go round - I'm only allowed in if I'm with OH!
It's very upsetting for everyone concerned, especially as she made no attempt whatsoever (even a decade or two ago when she was compus mentis) to prepare herself for old age in any way. She refuses even to make a will, goes off on a rant if a power of attorney is suggested. Still convinced she can cope, immediately forgets as soon as a crisis is averted, and still believes she's just going to die in the night!
It's going to take a major incident to get her into a home, probably something like a fall breaking a leg or hip or her setting the house on fire or it blowing up. She'll never go home again after a hospital stay as she's only just coping of a fashion by "muscle memory" in things like washing, going to the loo, microwaving a ready meal, or even opening a bought sandwich - and OH/his sister have to phone to remind her to make a brew, eat something etc - she can't even think to do that herself!