I agree with Jody...call 911 and then let HIM deal with it.
I'm a recovering addict, and I, too, threatened to kill myself if I didn't get what I wanted.
He's already been through detox, right? How do you know if he's going to "get it" THIS time? Do you really want to be manipulated and lied to any more?
He will find somewhere to go...we always do. He is an adult, and what he does is NOT your responsibility.
Focus on you, and let him find his own way.
Hugs and prayers!
Amy