Oh boy, lostmyson, I am so very sorry. I know how devastating it is for us parents. Hang on.
Try reading the article on detachment at the bottom of my post here. A good book many of us have found valuable is Codependent no more by Melodie Beattie. You may want to begin there.
It sounds as if you are at the end of your rope. That is a terrible place to be however often it is a turning point for us. We become aware of our powerlessness, our utter lack of control over the situation and over our adult kids and we begin the process of detaching ourselves from their drama, their choices, their lifestyles, their abuse towards us and start to accept what is. It is not an easy road, it goes against all our parental instincts and yet, as you mention, he won't get help, so there is absolutely nothing you can do. He is a grown man, he gets to make whatever choices he wants. What he doesn't get to do is to drag you and your family along with him. But the only one who can stop the momentum here is YOU.
You have to learn to put the focus back on to yourself and your daughter, who is very young and needs you to be present, not preoccupied with the shenanigans of a troubled and manipulative and abusive grown son.
There are shelters he can go to. You are not responsible for him. He is burning the bridges not you. Your job is to take care of you. And, you will likely need help. Most of us here need professional help to learn to detach and accept. Therapy, group therapy, al anon, narc anon, Families Anonymous, NAMI, the National Alliance on Mental Illness has chapters in most cities and can be accessed online. Seek out help immediately to learn the tools you will require to make this transition. To get support. To have a safe place to vent and emote. To get understood and feel empathy. To be heard. To feel acknowledged. If you believe your son has mental issues NAMI may be a very good place to start, they have courses for parents which are very good. They can assist you.
If you get yourself the support you deserve and need, you will begin to feel better. It is a slow process, we all fall down, we feel so much guilt and responsibility for our adult kids, it is very difficult, but you can do it, one day, one step, one moment at a time. But, please, find support.
You are not responsible for your son. You cannot control him. You didn't create this. You can't fix it. You can't fix anyone. All you can do is to learn how to respond differently, learn to focus on yourself, learn the tools to detach and learn how to accept what you cannot change.
I am so sorry for your hurting and wounded heart. You've been at this a long time. 5 years is too long in this kind of a hell. Be very kind to yourself. Do nurturing things for YOU, nourish yourself and begin to allow yourself to heal from the trauma of trying to help someone who doesn't want to help themselves.
Find support, keep posting here, it helps, don't respond to his calls or texts for awhile, tell him you will speak to him once a week, or whatever works for you, on your terms, not on his. Do not allow him to disrupt your life, figure out your boundaries and stick to them.
We're here if you need us.............hold on.........