Man this sounds familiar.
My daughter would pressure me EVERY time we got together... a weekend visit, a home pass... a phone call... Gad! It got so annoying!
She wanted to come home so she could use. Period.
She was sent to a recovery house after one rehab and though she ended up failing a UA following a home pass... it was a GOOD thing! Her drug of choice is meth - and every DAY she doesn't have that drug in her brain is a good thing. I figured 30 days in rehab followed by even one day in recovery house was one more day clean.
It turned out that she stayed in recovery house (clean) for two additional months (almost 3). That was a long stretch of clean time... nearly 4 months all said and done. It was good for her to get truly clean for a while. It helped her really see her situation and how far down she had fallen.
Her recovery house was followed by a period of being back out there... followed by a short, short stay at a faith based rehab, followed by back out there... followed by a court-ordered "choice" of rehab or jail. All of this happened from November to April... a short, but chaotic 6 month period of time. At that final rehab, she "got it" - she heard some things she had not heard before, and met someone who meant so much to her that they ended up getting married (I know! not my choice - but hey, she is STILL in love with him 2 years later...smile).
Her recovery did not follow "my" plan... at all. But it is her life and her path. And looking back, I realize I had almost nothing to do with it at all.
I hope your son is successful at recovery house. I pray that he can have an open mind and heart.... but even if it is just a few more weeks of clean time - that can help, too. Recovery doesn't have to be perfect to work.
(((hugs)))