I agree with mamya.
I sent my daughter to stay with my sister-in-law recently, because i felt her adhd behaviour was putting her in danger. It didn't actually last long in the end, but i felt physically heartbroken when she wasn't here. I posted on AB (it's in my questions, if you want to see).
Try to look at it as teenage experimenting - which i think is what it is. You haven't lost him, just keep in touch, as you are. I really think he'll be back sooner or later. You need some distractions for now xx