I know you're in for the long haul and I commend you.
It's awfully hard to be a caretaker and especially with a pwBPD. I took care of my mother as her dementia increased. Her doctor prescribed an antidepressant, which helped with a lot of the BPD issues.
He desperately needs your help and you have some leverage there as far as the rages. Only you know what you'd be risking by having him taken away for an evaluation. However, that could be a motivator for him not to continue to rage at you in the future.
My mother was hospitalized for heart issues and she kept pulling off the heart monitor and trying to dress and leave the hospital. She was very angry and abusive to the nurses until one of them appeared with restraints and threatened to use them. Then she became meek like a little mouse.
The nurse sort of apologized to me when I showed up to visit and I laughed and told her that was a great decision.