I'm so sorry for the pain you are going through. My 22 year old son is an alcoholic- recovering at the moment.
If I read correctly, he is doing drugs in your house and you could call his probation officer and turn him in? If I were you, that's EXACTLY what I would do. What you are doing now is not helping him. Keep reading here and posting, you'll gain strength.
Look at jail as a chance for him to get sober and hit bottom.