From what I understand, the Special Needs Trust is the way to go.
It’s specifically for Special Needs, so it can’t be used for their day-to-day care - this will allow your wife & daughter to max out all public assistance & hopefully prevent it for being taken for routine care.
I live in Virginia. Here, we have Intensive Community Treatment programs that each county’s mental health department runs. In rural areas, 3 or 4 counties may group together to have a central agency.
They can do a lot of things, like med management, driving them to & from appointments, and basic caretaker stuff. They would work with your daughter under dual diagnosis. They can help with housing & things like that too - basically, most of the things a caretaker would do. They even take trips to the beach or to go camping.
I think it’s a great program, but my son isn’t really ready to participate with them fully, even though he’s seeing a doctor & a case manager through it.
Even though I’m younger than you, in relatively good health, and plan to live forever, I want to keep him in the program so they can step in as his safety net if I’m no longer around.
If it was me, I’d be worried less about the money than who would care for them with the love and attention that you’ve given them.
They’re also used to working with the most severe cases through both medication and therapy. Maybe if you have something like that there, they’d be able to help them improve some.