I am sorry Jiggs, and I know how gut wrenching this is for you.
Sadly, for we parents of addicts, knowing they are in jail is often better than knowing they are on the street. At least they are clean and can get help there if they seek it, sometimes they can get drugs too but their odds of survival are better.
Keeping your son in my prayers, that this is a turning point for him or at least a valuable learning experience.
Hang in there, Jiggs, we get through this by walking together here.