you are amazing, it must be very scary, but you are riding that fear and taking control of your life.
I don't know if this will help, but re the guilt you are feeling about the bad place he is going to be in: everything that everyone has said about this being the result of his choices is spot on, he has to own his own consequences.
but also, I don't know about your ex, but sometimes it feels as if mine is a golden child wandering through life untouched by disaster as chaos swirls in his path, laying waste to those that he touches.
He has passed out under monuments in town squares overnight, in ditches up mountains in cold november snow & in gutters, without a hair on his head being harmed...he wanders home so incoherent and unco-ordinated that I am amazed he has remembered where he lives or managed to physically walk, without getting run-over as he lurches accross roads or falling down long drops. He passes out in the bath but hasn't drowned. He has bad debts that have shot his credit rating to the point where my (already poor) rating is adversely affected by being linked with him BUT he manages to get a mortgage and not still pay the outstanding debts.
I could go on... and this "luck" will not last forever.... but my H is an adult who is very well skilled (however subconciously) in finding lots of people who will help him not suffer the consequences of his actions. (moi for example)
I haven't worried about his physical or fiscal well-being since I realised how bleeping unfair that was!