Kuma,
I have been clean from meth and all mood altering drugs (which includes alcohol) for over 30 years as of today.

I went to a treatment center for 28 days where I was introduced to Narcotics Anonymous, a 12 step program modeled after Alcoholics Anonymous. Treatment centers can only give you the knowledge needed to stay clean. The members of NA taught me how to use the knowledge, how to live life clean, gave me a safe place to interact with other recovering addicts, how to dance clean, how to deal with people. In short, NA gave me a life worth living.
But nothing can be done until your son is willing to change. A treatment center can only keep him clean while he is under their roof, after that it is up to him to do the work. If he is unwilling to do the work the ends are always the same for the addict, jails, institutions and death.
Go to alanon, in person. Attend meetings with others who's life is being effected be the disease of addiction. You can find a meeting online or in the phone book.
al-anon.org
Everyone changes when they use, especially meth.
It's more than the 'high' of using he is chasing, the high left him long ago. He is trying to get back to normal, enjoying the adrenaline rush of scoring a sack of meth, enjoying the wheeling and dealing of the drug trade, enjoying the like minded women that are in the drug trade, the control and chaos. He has a long road ahead of him but you can not do it for him. Your job is to never give up hope and pray he finds the rooms of recovery before it's too late.