HOWEVER, just about universally they highly highly value their own kids getting college degrees. It is one of the most important things they believe they can give their kids. So while they skipped parts of the traditional educational system, their experience after 30 years of life has convinced them that their own kids ought to have it.
Schooling at the level you're at now is designed to be well-rounded, and I suspect you would be doing yourself a future disservice if you chose to completely reject it in favour of your current narrow interests.
he would be much better served reading broadly; historic fiction, science/nature periodicals, the classics etc
teachers like Tyler DeWitt are vastly underrepresented in the school system.
I'd suggest following hkmurakami's advice and figure out a way to bend the system to your will. It's a much more valuable lesson in the longrun.
What's actually super interesting about the kid's comment is that while clearly written by a clever kid, he specifically never states that he is too smart for this, and that seems intentional.
It seems very much that the kid recognizes that the system is flawed, and not that he is too extraordinary for the system, so in my opinion, trying to appeal to him in the: "If you were that smart you would've just finished it next to all your other stuff." sort of manner will be of no effect.
Now, I don't even know if I think he should stick around through school, I likely would not have, but if that's what you want to argue to him, I'd suggest that the best way to do that is through showing him how non specialized education is helpful all through life, which I argue will be very difficult, because we have an educational system that stresses specialization over a more liberal education, and I think he recognizes that.