"Your support doesn't have to be in the form of money, or a place to live, or anything more than an "I believe in you." Instead of him making his recovery conditional on you being a part of his life, why can't you make him being a part of your life conditional on his recovery? If this relationship is worth having, it will wait a year while he sorts himself out. At least."
Sparklekitty...so simply and well put and spot on.
In order for his recovery to mean anything...he has to make it happen on his own as if his life depended on it...because it does. You can support him from afar and leave him to it...and if he can succeed and improve his circumstances and his life on his own, it will mean so much more to him and to you. One thing I have learned is that everything we know about love and helping goes out the window when it comes to addiction. It's all so counter-intuitive. Letting him stay in jail right now is likely the best thing you can do to help him.