Thanks very much for the insights, everyone. Very helpful!
I can already see that making sure that we keep up with activities/identity separate from "caregiver" is going to be important for us, as well as figuring out which care can be paid/outsourced and which will be best for us to do. So easy to get completely sucked in to the caregiver role, then overwhelmed and cranky, which negates the whole positive intention of being hands on.
I've also found that I really need to let go of my thoughts of the "best" way to do things or the "best" outcomes. As a former successful administrator, this is hard for me! MIL has her own ideas, and even if some of them are objectively bad (e.g. underspending on herself for necessary things; under medicating her pain) there's no point at all in arguing directly with her. Better to find a way to deal indirectly (e.g. POA, meds in bubble packs) or even let some things, e.g. regular baths, go entirely. Whew! That last will be hard once she's staying with us. Febreze for the win. :(
Despite the frustrations, though, we've already had good times with her and we know that our interventions have meant that she's been living better in her house in the last while than probably the last 10 years (daily visitors, de-hoarded spaces, regular meals, clean bed linen and clothes). Not to mention all the co-ordination needed between doctors, hospital, home support services and more. If we were out of town, we would absolutely need to pay someone for this role. No way a stubborn, frail, and sometimes confused senior could deal with this.
Our province (BC) no longer has non-emergency waitlists for public care homes but as she can afford private care for some while, that is the route we'll take if/when necessary. Her desire is to stay in her home and she has the means to do so BUT she will have to accept a lot of in-house care to make this happen once she's declined further.
For now, we're going to take her in to deal with the immediate medical issue (daily radiation to manage the symptoms of a painful cancer) and then reassess. We'll also take the opportunity to continue de-hoarding her house, which she has given permission to do.
I've helped a parent through a terminal illness in the past but we knew the finite time frame. The long drawn out decline of old age is new territory. And since I'm older now too, it shines a light on my own decline/mortality. I have read the excellent Gawande book. Much to reflect on!
Modified to comment on this - "A few months ago, my mother explained that even the Queen had paid help, and if it was good enough for Her Majesty, that GM can tolerate paid help too." Hahaha! We've tried this too but so far it hasn't worked because according to my MIL the Queen is "used to help". How many families in the UK/Commonwealth are trying this tactic?