Re: loosing control
I dread the teenage years with 3 boys! Its a time when their hormones are raging and they feel that they're adults now. They do not want to be told what to do, how to do it or with whom. They're asserting their independence.
The best thing to do is avoid lectures and demands. This approach serves only to make them more defiant and rebellious. Talk things out, keep communications open and talk in a way that isnt condescending - let the teen come to his own conclusions about making the best choices. Guide him rather than tell him what to do. Ask him about his friends and their activities without being judgemental!! Talk things through calmly! And make mild suggestions rather than demands as far as what he does and with who. He will hear that much better.
Most teens will evolve away from religion for a while. If you dont force the issue, they will return on their own when they're ready.
As far as hanging out with non-desi I think the only issue would be that alcohol is not forbidden. But it IS forbidden (in USA anyway) until age 21. So if he and his friends are teens and drinking, they're breaking the law. Talk about this.
If he is dating a non-desi girl, so what? Teen romances typically burn themselves out. And if he does happen to marry a non-Muslim, that isnt the end of the world either. Muslims are allowed to marry "children of the book" which includes Christians and Jewish. I was raised christian and my husband and I are raising the boys Muslim. This has never been an issue in our family and we have had a very happy marriage for over 10 years.
Just guide him to the right path instead of dragging him down it with a leash and collar and he will find his way.