I'm scared..I don't think he has much time? Maybe he is dying?

Children can't choose their parents unfortunately. It seriously sounds like you dad is in a dangerous mental state and it is difficult to know what to tell you. It would be easy just to tell you to get psychological help and for your father to get the same. I expect there might be social services out there who could offer help at low cost. The hard part is convincing your father or others to get such help.