Hi Cat,
I'm sorry about her situation (and your poor sister's).
I'm not sure what it's going to be like to be very old if I'm that lucky, but as I've been living with a very old woman (strong N characteristics but not NPD) -- and know her intimately and have observed her decline daily for the last more than 8 years, I have some thoughts about this I never had before.
I think some of elders' denial about their condition is fear. But I'm coming to think another part is just plain resistance to dying somewhere else. If home is a familiar secure place, it may be that unconsciously, refusing to do what's practical and safe is a last declaration of independence.
And in a way, I've come to agree. Unless there were terrible suffering OR unbearable burden on family, I believe my mother would rather risk dying alone at home, than move into a facility.
She's always been rational, but she has interesting forms of denying things and maintaining control that do increase her risks. For example, though it's been explained to her over and over, she does not wear the emergency pendant I got her. She goes to the other end of the house, leaves it on her dresser as though she should just wear it when she feels worried for some reason, not all the time.
Result? One day she may be in one room and have a fall, stroke or heart attack, and I'll be at work or at a meeting. This is a risk I think she is unconsciously taking intentionally.
I hope the solution for you and your sister and your mother will be the one that makes sense for you...I apologize, haven't read your old posts in so long I don't recall your descriptions of your mom.
She may be someone who truly must be persuaded or semi-coerced into moving. I know that happens so please don't take these thoughts as critical at all...
I also know how absolutely desperate caretakers of the elderly can feel, and what a health price they can pay for enormous and very extended stress.
Please call on all the senior organizations in that community (you can probably do a lot of the homework by email) and ask where you and your sister could find a geriatric care manager. This person could give you very specific advice on how that kind of conversation would go as well as it could (and it's likely a process of several talks over time).
Hops