This is his problem to resolve not yours. He does have someone, himself...the ONLY person that can get him clean and straight. His bad choices are why he is going on the street, nothing you say or do will force him into recovery or keep him out of prison.
If it were me, I'd not answer his calls, I would let him roll.
As for your fears, you are awfulizing and projecting, doing that is non productive, it accomplishes or changes nothing. The only thing you are doing is upsetting yourself.
Prison may be the answer, I do not know, he will have 3 hots and a cot. All I know is that
he must fall to his knees before he can get back up and seek recovery.
I know that you are in pain and I am sorry. However I would suggest this....:codiepolice