Has it dawned on you that he is refusing care because his life has been shattered and he has no one to rely upon? He probably feels like why bother any more. That he does not have the means to go out and find a new place.

Imagine having health issues, constant medical appointments, and then all this happens. How was he getting to his appointments? You have zero understanding what your father has been through and I'm sure he understands that he cannot rely on his family in his time of need. What would you expect from you father if the tables were turned and you were desperate?