I'm reading this, Erin, and feeling so sorry for the struggle in your home, by everyone living there.
Please keep pestering whoever needs to do something to get the hand controls. Sometimes you have to pester to get attention. We are trained to be patient and think of others, which is VERY GOOD, but there are times you have to just fight for your needs.
That's what happened to me after the Cerro Grande fire here in 2000. I was the only one who could fight FEMA for the insurance benefits they promised when they took over our home insurance because the fire was started by a gov't employee doing a "prescribed burn." My husband was no longer able to fight, at that point, sort of like your dad, just ran out of ability to cope with all the myriad stresses. You have to be a fighter now, even if you are ill. Not fair!