Coach, part of me doesn't want to question your judgement since I suppose your reasonable as a parent and coach, but I have to ask....
Why not coach your kids, or any who are interested in running, yourself? I know you don't want to undermine the school coach's authority or teach your son to question everbody and never do what he is told... but wouldn't he be better off, and a better runner, in your hands? It would be easy to say 'Another coach' has shown us that teenage running isn't necessarily school-affilated. Although I greatly respect what they are doing with the club, I won't go so far as to give credit for unattached running because it is an old idea. It's what I did in high school.
40 years ago, and before that even, a lot of teenagers ran without their schools being involved. I totally understand Another coach's frustration with the school system and your lack of enthusiasm and confidence in it. It seems as though sprints and maybe mid distance races are difficult to access unless you're national class or better, or affiliated with a school. But anything 5k and up is ridiculously accessible.
What my peers and I did in the '70s and '80s is train, race, and not even tell the school about it. There were so many competitors in our age group at most races that we didn't know and had never heard of most of them. It certainly wasn't just the crowd from our school. I mean, we never swept the 17-and-under podium because there were simply no other entrants. It would not be unusual for none of us to make it onto the top 3 in our division, despite the fact that I was pretty dedicated and did more mileage than most teenagers today.
What I describe is a world where sports participation without school sanction was socially acceptable. Parents approved of it, and in my case, my friends didn't pressure me to get on the track team. They didn't either. When this changed I don't really know. (Maybe the early '90s??) What IS clear is that after some point in history, the rule became: If you run, you must do it for the glory of the school. I'm not saying this is any State law, but if peers and parents enforce it, it has more effect than an actual law (like drinking age).
Maybe this can change back. You parents of teenagers active on this thread may not remember what I descibed, but some of you reading who are old enough may. This is why I endorse what Another coach is doing. It questions the mindset of 'your school must govern your sport' mindset. You, coach, could in theory make a small change. It may affect more than just your son. His friends could see what he's doing and view it as better than the school's program.
I can't tell you how may threads I have seen started by teenagers to complain about coaches. This thread, populated by parents, coaches and general older folks like myself, also shows how bad these programs can be (not all are bad, for the record). I never complained once about by high school track coach - an assistant football coach who needed to keep an eye on his squad during the other semester. I never met him.