How To Curb Tendency To Take Over Dose Of Pain Medication?

Question : Doctor, I'm in a rough situation. A friend of mine sees a doctor for his knees he is prescribed 30 percocet a month. They are gone in 15 -21 days. He is also taking Tramadol. He takes 8-10 at a time. This is always. He is getting the Tramadol from Canada. I don' know how he did that. He has a bad back disc and very bad knees. The family tried to talk to him about his usage. He went ballistic. I have talked to his brother and another close friend and I found out that he divorced his wife so she couldn't control his pain Meds. Now he is drinking a bottle of Nyquil every other day. I know he totaled one car because of poor judgement. I found out that he totaled another several years ago. No one was hurt just his cars. He doesn't drive because he can't afford a car. I used to take to take him to get his script and to the post office to pick up the Tramadol. This is an actual event that happened on a Friday. He calls 8am by 10 he calls. He is getting pissed. I had takin him to a dinner a breakfast. He starts complaining about it is taking to long. I drop him off at home. At 3:45 he calls me to pick him up to take him to the medical center where the doctor is. He is now going ballistic. Every cuss word you can think of is coming out. I'm going to stay there and He will give me my script. Now the time is 4:15 And the office shuts 5. He starts beating his upper thigh with his fist and started pounding my car. I yelled at him to nock it off. Took him by surprise. We got there and he got the script. The doctor had just done it and had given it to the receptionist. He came out fuming mad. Now there was another time that he was going in there and raise he'll till he got what he needed. I thought for sure that security/police would have to come there, but the script was there. I know who his doctor is. How do I go about seeing him and telling him what is going on. Then other part is once the doctor is told and he will go ballistic. I know he will become combative. I am presuming that he has been doing the drugs for at least 5 yr most likely 10. I have known him 3 yrs and his other good friend has known him 13 yrs. it seems like no one wants to take the next step or are afraid of what will happen to him. HELP I NEED ADVICE!