My experience is much like pp, I'm not quite to teens, but I was a very very drug/danger seeking/depressed teen.
I was very very lonely, and my parents treated me like I was a hassle, from my perspective. They never seemed happy to see me, and I felt I couldn't do anything right.
I think having more attention in just listening and less judgment in tone from them would have helped. My SD did not trust me to make any decisions or anything really, so I was controlled to a point of excess, and it was a viscious sp? downward spiral.
I think you are far more engaged and caring than my parents were, but teens seem to feel things intensely so he may still feel similarly.
Things I loved when I got it:
My mom would randomly stroke my hair or hold my hand.
my mom would listen to me in the car.
my uncle let me come over after I got in really big trouble and fractured my eyebrow when I was drinking, he held me and didn't scold me or try to give me any advice, he just gave me love and listened.
Sd asked if I wanted to get a CD and sat and listened to the *entire* Slayer Reign in Blood CD even though it was probably torture to his ears, and he didn't give me an opinion.
I liked it when they let me in on secrets like what gift they bought for someone and asked if I liked it or thought it would be a good gift.
I liked being asked along to go grocery shopping - probably because they worked so many hours, but I liked being included.
Eventually for me stuff got bad enough I moved to my Grandma's which was the perfect cure for me, because she was home all the time and gave me a clean slate. She treated me like I was trustworthy and so I was. She just wanted the who what when where and for how long. My SD was mentally/emotionally abusive so I imagine that drastic step wouldn't be necessary for you, but some of Grandma's tactics might work too.
I hope some of that helps!