Pravchaw any kind of therapy whether inpatient or outpatient, if he is willing to go for any amount of time is good. My 23 year old AS recently completed an intensive outpatient program and completed it. I never thought that he would actually follow through. One of the things with addiction is that he has never followed through with school, work, etc. This time he did. It is still hard and he struggles but he is in a way better place. I am proud that he finally completed something. At first he was reluctant about the 12 steps and NA meetings. Soon after he realized on his own that he needed that and didn't mind the drug tests or going. Now at this time, he's not attending aftercare but he is still seeing his doctor and scheduled to see his therapist for individual therapy. He's also see a primary physician to get his health back on track.
I also realized that they are on their own time frame. In family therapy, I remember the addiction counselor stating that she often has to speak to addicts like children because even if they are 40 years old they developmentally stopped maturing somewhere around their teens. So be patient.
Take it easy. We as parents tend to jump to conclusions too fast sometimes too. Focus on the positive that at least for today he went to seek help even if it is just a three week program. With any luck, it will turn into a six week, 12 week, etc.