Tulip...tell him to go to the doctor. Spend at least a year clean and getting his life in order. Once it is in order for at least a year make a list as to what he has changed and why he deserves you. At that time, if you are still interested, talk to him. If not....nothing will be any different.
What I am saying here is ACTIONS FIRST! They can talk (I mean quack) all they want...but the LONG TERM ACTIONS is what really shows someone your behavior and personality.
Good Luck and God Bless.