[911Rob]

I feel for ya bud; but remember this.... even the tiniest bit of help from you will make him worse! Trust me, it will. Look at all the help you've given him and what did it result?.... worse.

Tell him that.
Tell him all he needs to do is admit he needs help and get on the wagon.
"Professional" help.
Tell him he's destoying his mother and you can't allow him to talk to her anymore until he starts to clean up his act.
He is right where he wants to be; it was his choice.
Be positive, firm and decisive when dealing with him; he'll understand that you mean business. You're not confronting him, you're at his side, but he has to take the steps on his own, under his own free will.

Good Luck!