So sorry you are having to go through this with your son.
The four months my son spent in jail really changed him for the better. He's never been back (thank goodness!) He is a good family man now and you'd never guess he'd ever spent time behind bars.
Back when my boys were getting into trouble, I found a listening ear (cornered him in his office, actually) and blabbered on and on and on about how if I didn't do this or that my son was going to jail. He just sat there and listened. When I finally stopped long enough to ask him what to do, this wise man told me with a smile, "Just love 'em."
And so I quit trying to solve their problems and just let them suffer the consequences. That was the best advice I was ever given.
Just love 'em. Prayers help too! I'll remember you and your son in my prayers and hope you will feel comforted through this tough time. They really do eventually turn out just fine.