Confused, frustrated and heartbroken

I dont know old old your son is. Mine is 18 and is a senior in highschool. He smokes weed and is addicted to Zannax. He agreed to a outpatient treatment and has missed 2 meetings already. He justs tells us what we want to hear. Because he missed his last meeting, my husband turned off his phone. If He he doesnt go this week, he will take away his car, then the last thing, to ask him to leave our home and find somehwere else to live. I am learning by my Al-Anon meetings and what I learn from our counselor is we can not be enablers. We have given my son a warm bed and all the food he desires, and his freedom to come and go and he continues to use, although he doesnt steal from us, I have to tell you I had a brother who was stealing any pills he could find in my parnets house. He also forged my fathers name and opened up credit cards to pay for stuff and get cash for his use. My mom did nothing but tell him to stop, she did a lot of crying and felt sorry for him., but it got him no where. Love doesnt heal all, trust me. I too, am afraid my son would kill himself. He always had ADHD-ODD and that had symptoms of their own, but now doing drugs and pills, it magnifies his problems. I always want to know where he is, what he is doing and I am not settled until he walks through that door. I am always praying to God to keep him safe...I cant live like this anymore. He doesnt care how worried we are and what he is putting us through. Al-Anon teaches us that after you have done all that you can do, sometimes, you have to practice tough love and let them go. I am learning that I can not let him destroy us...I have an 11 old to worry about also. I am not in great health. I lost a lot of sleep over him. We have both aged tremendously. I know its not here yet, but I think soon, my husbamd will turn him out. He has no where to go. Last time he kicked him out, my son hated it.,He slept in the woods with no where to go. His so called friends couldnt help him. He begged to come back and said he would quit and go into treatment. Like I said, he already missed some and by reading his texts, we know he is still using and being disrespectful in the house...we too are sick to our stomachs. We need to follow what the experts say...it wont be easy mom, we are just creatures of nurturing and love, but those don't help when an addict is concerned. His love is the addiction. He must hit rock bottom in order to come around, at least thats what we have been told.