Replying to Intervening with a heroin addict. HELP

Here goes... one of my best friends is heavily addicted to heroin. If he has money, he is buying heroin. The other day he shot 5-6 bags of it and I do not think that is terribly uncommon for him. He probably does it 5-6 days a week and takes a suboxone when he doesnt have the money or cant get it. If he has coke, he is speedballing. On several occasions I have seen him drink while speedballing. It's really bad. He's (was) actually good friends with Tom Warnick.

He went to rehab in high school, but it clearly didnt work.

My friend and I tried intervening with him tonight, but got nowhere. His dad and sister have tried on many occasions, but have also failed miserably. His mom is a raging alcoholic who has liver cancer but still wont stop drinking. She has 4 DUIs (3 in MA, 1 in NH).

Basically, he goes back to school at plymouth state in a week or so and we need to convince him to commit himself to rehab and take a semester off.

Worst part is he's literally the nicest kid ive ever met in my life. Wouldn't hurt a soul.

Tips, suggestions, anything? Tonight he just kept saying he wasnt ready to help himself even though he admitted he had a problem

I also leave for school soon so it is urgent that we intervene soon.