I understand that you think he would die if you made him leave but you will live in chaos indefinitely if he stays. I think you should give him an ultimatum about getting help and if he flips out have the police at the ready to intervene. If you feel like he is a danger to himself or others you can talk to the police ahead of time and have them take him for a 72 hour evaluation if he flips out. You are not helping him any by letting this go on.