know what state to move to to avoid them.

Not US-based, I am afraid. But we're trying to figure out a way to legally bypass some laws for the future. Basically, when a (elderly) parent is in need of care but can't pay it on their own, they (hospital, retirement home, ...) will turn to the children. Of course, nmom will demand to stay in the most fancy place ever, which is not happening on our watch.

hoarder, hypochondriac, and probably other problems

Yes, yes and yes. Everything little "piece of art", every book or dvd you see in granddad's house is hers. He barely has room to keep his own stuff. He spends most his days in a shed in his backyard because that's the only place she hasn't touched yet.

Congrats on your engagement

Thanks!

So she will not have as much money as she wants to, but she will not be destitute

She'll make herself destitute. She'll spend all the money she gets on stuff she doesn't need. She won't be able to pay for stuff like electricity or water and she'll have to turn to other people for that. That's the way it's going to be, I am sure of it.