Ah, that’s good to hear! Seems like you are increasing your understanding of his ADD, and I am sure he will both make steps and appreciate it =)
I was also obsessed with video games. (Still like them, but replaced my addiction for gaming, with music production)
On the other hand, a career in video games is actually possible in the time we live in.
Turning off the internet when he needs to study might help. Then it won’t be a choice/distraction for him, and he will have to do something else. But I would try to talk with him and agree on the times and rules for this so he gets a sense of being listened to. And also, he won’t be able to complain later since he was part of the decision himself.
The fact that he went to the doctor himself is a good sign. Let’s hope the new pills will work better. As for a magic bullet… The pill will rather help him find the right path. He will still need to walk it himself. I am trying out ADD pills for the first time in my life this week, and even though I was hoping I would suddenly get an urge to be productive for a whole day, I still find myself sometimes doing other things. So it obviously needs to be supplemented with some techniques and routines.
As for finding an obsession for him, feel free to send him my way if he is interested in music =)
I have managed to get to a professional/semi-professional level in 2 years or so, way, waaay faster than most people. And I attribute it to replacing my gaming addiction with a kind of music production addiction/obsession.