If he promises to go to rehab tomorrow I would let him come home. He called once which shows that he is trying to stay connected. I know you want so bad to say the right thing and felt inadequate as he walked out that door. Do you have the means to get him in a long term program til he is 18 because 3 weeks won't be enough as he is still very much an addict.There are some great youth programs in Arizona and Utah. Don't give up on him and do everything you can to get between him and the drugs before he turns 18 and you have no parental control.I know this is a tough time and I wish you the best in trying to connect with your son and get him into the treatment he needs.