Honestly, every case is so complicated there really is no right answer. You may have to continually reevaluate the circumstance and adjust. It is not like there is one right way to do it. I strongly recommend you find a counselor for yourself that can help you talk through this. Many churches have counselors for free. Look for a church that is really big, and they are more likely to have one on staff. Many have worked at other facilities, but for whatever reason have chosen to switch to churches. I think you need to make sure you are caring for yourself before you attempt to care for him, otherwise, you are both going to drown. If he is refusing help, you need to be able to remove yourself from him, until he is willing to seek the help he needs. A counselor for you will know what you can and cannot do, and also help you see what is the right way to deal with it for you. A big part of it is putting up boundaries, but boundaries are going to look different for everyone based on temperament, personality, etc.