Chicory, sweetie,
I'm a mom, too. I do, I DO get how hard it is to watch one's children make horrible choices.
Yes, to some extent, he is using you. You are, however, permitting it. Maybe not willingly or completely voluntarily, but you are the ONLY one who can change the situation.
The only way to do it is to do it. Nobody is going to be able to give you a magic way to do it painlessly. It isn't likely that, one day, having gotten enough support and recovery here and at Al-Anon, you will be able to do it painlessly. It is going to hurt, no matter HOW much recovery you have.
My sense is that you are more afraid you will be unable to bear the pain, than you are afraid of anything else. I'm not saying you don't care about him. But I think it's your own fear of your own fear that is holding you back more than anything else. I've heard you say over and over how much you would worry, how you wouldn't be able to live with yourself if something terrible happened to him after you kicked him out.
It isn't so different from when I was still drinking and could not IMAGINE having to cope with all the stresses in my life, sober. You are in bondage to him, every bit as much as I was (and he is) to alcohol. The only way to stop is to stop. I think if you could only see that you WILL be able to survive the pain of kicking him out and doing what is best for yourself, you will start to have some faith in his ability to do the same with the alcohol, when the time is right.
Change is scary, uncomfortable, and often downright painful. You are a strong person. You have lots of support here. You have a HP who will get you through it.
But you gotta LET GO. Have faith that you will get through it. You can't stop him from drinking whether he is there or out on the street. This week has proved that, hasn't it? Your friend couldn't save her son's life. Are you so much more powerful than she was? Do you think if you love him harder than she did, it will make a difference?
Hugs, I know how hard this is for you. But I think you are stronger than you think you are.