Dad is in rehab after a hospital stay and hating it, wants to go back to AL. Which I totally get. But every single thing that he is unhappy about is my fault, in his mind, which is failing. Every visit is just a litany of complaints and grievances, every phone call is him screaming at me that I've locked him away and I've ruined his life. In his more lucid moments, he calls my out-of-state sister and complains, and then she contacts me with her "concerns." If I say I'm sorry he feels that way, I get screamed at ("you always say sorry but you never do anything!"). If I walk out — and I have — I get a groveling apology for like a minute, and then the bitching and moaning starts again, and if I am not sufficiently attentive then it escalates to yelling. My husband has witnessed this and is supportive, but feels like I need to understand my Dad is paranoid and having cognitive issues. But Dad doesn't yell at HIM. (Or at my sister, with her "is everything okay with Dad?" texts) I leave every visit feeling like I'm bruised and battered.
Your father also appears to be experiencing a lot of anxiety and frustration. He is probably scared and it trying to exert control over his circumstances. Unfortunately, he has decided in his mind that you are responsible when actually it was his weakness and fall that caused his rehab stay. Please talk to his doctor about evaluation for dementia and mental health issues. He might benefit from a mild anti-anxiety medication while you are also implementing your "boundary plan."
Time to step back. Don't visit as often and if he gets started say goodbye. If he calls, don't answer. The Caregiver always gets the nasty side.
If he winds up making no progress in rehab, Medicare will stop paying for his stay and he'll be released back to his ALF IF he's in good enough shape to go back. If not, they'll recommend he stay in their long term care section of the nursing home instead. It's really up to HIM how things turn out.
Wishing you the best of luck taking care of YOURSELF in addition to helping dad.