i know this, if i were put in inpatient therapy by my mom, it would only send me off on a binge when i got out. i would take as many drugs as possible. if u want to help him, ask him why he uses drugs. if he says "for fun", then he doesn't know or doesn't want to admit the real reason. i used to think i used drugs for fun, but really a healthy person can have fun withoout them. find out why he's in pain and that can REALLY help the process get started.
best of luck!!

I can definitely relate to the first part of your post. I've definitely experimented with many many other kinds of drugs, even gone on a few small "binders" with a couple of them. I'm about as confused as it sounds like you are as far as why I always came back to pot. I love the highs I got from those other drugs, but just never let them become much of a problem I guess, pot's always been the problem for me.
I've been put into a wilderness survival type of treatment, and a halfway house both by my parents. At first I was very resentful, as any 15 year old would be. But I think if it's a good treatment center they should be able to show him why he's there and he would eventually understand that you were only doing it out of love.

While pot may seem a lot less harmful in the short term when compared to other drugs such as speed,coke heroin etc,smoking poses a real threat to an addict in that they are a)still feeding their addiction and b)when an addict continues to do this his/her resolve to stay away from other drugs is severely weakened.
This isn't the case for every person who smokes pot..but sadly it is true for every addict/alcoholic.
And for an addict who 'just smokes pot',it will never be 'social',or 'just every now and then'...for the addict the amount will continue to grow as he/she struggles to keep up with their ever growing resistence to the drug, until they have to smoke huge amounts,not to feel high but just to 'feel normal' and avoid what is known as (quite bluntly)the 'drug shits'..when one feels like crap because they have run out of pot.
Once their tolerance starts to build up and they no longer get the 'buzz','high' then comes the real danger of the addict picking up other drugs, to feel wasted, get high,out-of-it(it can also happen after the addict has restrained himself and 'cut back' on his smoking,the frustration and desire builds up and they have a binge.) Which in many many cases starts the 'poly-substance abuse' all over again.
I used to delude myself into believing I could 'just get by on pot'..I was smoking an ounce of high quality green every 4(5 max) days,between 70-90 cones a day, then went on to smoke joints (20+) because I couldn't breathe with all the bongs..and the stupid thing was I DID NOT GET HIGH!!! So periodically I would drink (disasterous) or swallow bottles of xanax,valium,serapax (disasterous...ended up in emergency 2 nights in a row,drips,oxygen- I had stopped breathing properly for several hours..they thought on both occassions I would die- this was after running out of dope,picking up prescription tablets to 'get through the drug shits',drinking on top of several bottles of xanax+sleeping pills because I wasn't in control of my bloody head,obviously)..I'm sure you're getting the picture...what can you do?? Have you looked into the possibility of out-patient treatment? Alateen?(A.A for teenagers)Have you checked out Al-Anon for yourself?That is what I suggest.And don't be fooled..If you believe your son is an addict- he will always be an addict and always at risk of upping the stakes until he comes to terms with that fact and seeks the proper help, and Gets Sober.