Hello Cholila,
I am sorry to here that you have found yourself in such a difficult situation. I don’t claim to be a physic but I thought I would reply because I can physically feel your desperation. I’m sorry if this doesn’t help you,
I can feel that your son has lost his way and is looking for a way out, there could be something he is not telling you that is making him extremely unhappy and causing him to act out specifically towards your husband.
Unconditional love can be really testing and often painful, both your son and your husband have been placed in your life to teach you specific lessons and vice versa. When your son chose you to be his mother and enter your life again (by option or not), he did this because he knows that your guidance and ability to love him unconditionally would help him grow and be able to become closer to achieving his life purpose. It sounds like now more than ever he needs your support to become independent and believe in himself again. I sense a lot of anxiety and pain from your son and anger/feeling helpless from your husband. Your son needs TIME for his emotions to settle about something he is struggling with internally.
I would sit with your son and husband and write down on a piece of paper your boundaries for living together as adults and all sign it as a family, it sounds silly but this way everyone feels involved and listened to.
As hard as this situation is for you, your son is going through a time of pushing away the people who love and can help him. He needs your support to get through this phase of self destruction and only through patience and kindness is it possible to resolve. We are all in pain at times as humans, sometimes we need to remember the common purpose is just to love and be loved in return. Spending time together alone with your son might help to build some trust back again to gain some insight into his thoughts (when he is ready). Just knowing you love him with expectation of an explanation for his behaviour, and reminding him everyday that you’re there wether he needs you or not, will help to take the pressure off him.
I hope this helped. Sorry if I didn’t. I really hope you get some sort of solution to your problem.
Peace and love your way.