Schizophrenia. What do we do about it?

Hi, My father suffers feom schizophrenia but he refuses to go to a doctor. He went once years back and the medication which the doctor provided is the one which we still follow. My mother went to the doctor and told him his condition and he changed the medication accordingly. But currently the doctor is no longer available and the medication is not working. He is not going to go to the doctor. So what do we do about it? He speaks to himself, we can't make out what but he says stuff very softly. His lips move and when we ask him he says nothing. He gives away money to people in fear and is always in fear. He won't go out of house except for morning and is always lying in bed and refuses to do anything. His diabetes is also increasing as he doesn't walk enough as he is afraid of people he won't go outside unless necessary. He doesn't talk much or rather I should say he can't do it. I stay away from home and I don't know how to handle it. My mother is getting sick trying to care for him.