My heart goes out to you and your son. These are very difficult decisions to make. I would pray to my higher power and ask for guidance and strength. Two of my adult children are in active addiction/drinking and they have children that I have no control over. I gringe at some of the things my grandchildren have to witness and deal with and hate it for them. I have to daily remind myself God is in control - not me - and trust him to work everything out. It is very hard and of course I want to fix it all but I can't. You have more control over the safety of your own child and I think that conversation regarding not getting in the car with anyone that has been drinking is a great place to start. Keep going to Al-anon and make yourself and your son your number one priority and let your husband suffer the consequences of his own actions. Learning about boundaries and setting healthy ones might be helpful too. Good luck.