Coming from a drug addict (I don't drugs anymore but addiction is for life) I would press charges on him. I hated when I would go to jail for Possesion and I'd feel all types of resentment but in the long run it helped get clean and I'm actually ALOT better off and extremely happy. Though your uncle might feel anger and frustration, being sent to jail and rehab works for most. Sometimes you just have to hit rock bottom before you realize that the cause of this misery is ones own fault.