Phase Two (three? four? I’m not sure)

So having returned from Reno and the Mensa gathering (I hope to post about that later today) I head off by Amtrak tomorrow to tell Mum that my sister and I are moving her to Durham (once we find a suitable place) and her partner is (at last report) heading to Portland to be with one of her own kids.
This is not a decision I agree with (neither do Mum & partner). Despite the considerable challenges of keeping them together, I think that ultimately they’re better off that way than parted after 35 years. I’ve even suggested we look at moving both of them here, but that’s a no-go.
I don’t find that unreasonable: I’ve already stated that I can’t guarantee showing up every time Mum needs something (one of the reasons for moving them to assisted living is to minimize the number of times we have to do that sort of thing—we’ve also discussed hiring assistance for little errands and stuff), so Partner’s kids may justifiably think they can secure better care if she’s with one of them (and her daughter in Portland really wants her Mum there). And I suspect some of them believe that it’s less stressful for Partner not to see Mum go down hill than vice versa. Certainly some of their arguments (that we’d expect them to pay for Mum’s little expenses, whatever they may be—or even large ones) are bogus, but some of them aren’t. I still think it’s worth trying to put them together … but it’s not to be.
Theoretically we could ship Mum out to Portland and move her in w/partner, but since Partner’s daughter doesn’t feel up to taking point with both of them, that’s not good for Mum and not fair to the daughter (it feels uncomfortably like shoving my responsibilities off onto her).
Part of the reason I feel uncomfortable is that they’re not senile yet: Even Mum, addled as she’s become, is capable of articulating where she wants to go, and Partner has too, and they both want to stay together (and if they were legally married rather than just married emotionally, I doubt we’d even discuss separation). We can override them because neither of them can set up a move without our help, but I feel like we’re crossing the line from “You’re doing something that’s harmful to yourself and we’re forcing you to stop” to “We don’t like your decisions so we’re making you do it our way.”
Much as I strongly believe splitting them up is a bad decision, however, it’s possible I’m wrong, so it’s not like I’m cursing Partner’s kids out for disagreeing. I admit that over the past week I’ve privately cursed out everyone involved, including Mum [which isn’t fair] but I don’t stay angry for long. It’s a tough choice and there’s no sure-thing perfect solution. I think this is less perfect, but that’s not certain.
And that’s the way it is.