ONly serious replies please ..What would you do?

Well here it is in a nutshell so to speak. I haven't worked in 4 years. Disabilities became sick 4 yrs. ago and found out i have a genetic disease. And severe scoliosis. Anyways, i went to a interview yesterday at a homeless shelter for volunteer work. I really have some problems with my adult son of 24, mentally ill. He is always/most of the time homeless and hungry, he is verbally abusive severe, and is can be psychical abusive also. I want to do this volunteer work, but I have been in a depression, major chronic depression for 4 years. I need to stop worrying about my son and get on with my life, but I am worried where it is coming winter that he will be homeless again, and yes, i have tried counseling for him he won't go, put him on meds, he throws them away, he was hospitalized for 3 days they let him go. He has to go to court AGAIN, he said he mistakenly took a soda for rite aid and they called the police. He won't go for help, he won't take his meds, he can barely go in to the store to get food because of his anxiety. I am constantly crying and sad because he won't get help. My husband has just about had it, my son was here last night and stopped by briefly and was talking to me and said hey mom, you need to get a real man , oh just kidding to my husband and they do not get along and there has been violence Between them both a few times. My husband tells me , no help until he gets himself help. but that is hard for a mother to hear.My son is always in need of something.... always. should i do this volunteer work or stay home, should i keep helping my son, i have cut back or stop completely?

After reading this i don't even think this makes sense, i have too many questions and not sure how to ask :(