I think the whole stimulants turn them into zombies is way over sold. I also think that if there is a bias in the culture against diagnosing ADHD you will likely have a hard time, as there is no definitive test. I wonder if you found an expat doctor whether you would get someone more inclined to hear you out.
How you describe J--has social skills but lacks some of the self control needed to practice them on a regular basis is so much like my youngest son.
It is possible that stimulants won't help him, but the catch is that you don't know until you try them.