In response, here are some "deals" that my friends cut with their teachers:
Friend 1: Instead of doing ~50 easy/medium difficulty math problems per night, he would do 3 difficult ones instead from the section.
Friend 2: He would not have to any homework for AP Physics class as long as he got an A on the previous exam.
AP Bio Teacher: Had an official rule where any student who got a 90% or higher on the previous week's exam wouldn't have to do any of the assignments for the week (though many would do the assignments anyways to learn the material).
These are some things he could look into.
I was in a very similar position as you and looking back what got me those breaks were the teachers that liked me, that liked what they saw in me and who wanted to support me.
Everything I got, I was granted. Just like in real life.
I may not have the "best" social skills, but I will say many of the teachers do like me.
they want him to conform to a system that was never designed for him
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.
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.
Don't get me wrong.. for most kids, I'd suggest going ahead and sticking around HS and finishing. But it's not very long after high-school when your high-school "credentials" become totally insignificant.
and just to give that statements some context, I've been in a position to make the initial decision on hiring at three of the last four companies I've worked for
"If you were that smart you would've just finished it next to all your other stuff."
It's not about being that smart, it's about the best use of your time. You could be the smartest person in the world, but doing hundreds of single-variable derivatives isn't going to teach you as much as moving on to multivariate calc (if you're capable of moving on).
School in the US locks you into a specific speed. If you learn more, you're punished with busywork below your current level, if you learn less, you get left behind.
The quote I'd prefer to hear your friend say is "If you were that smart why didn't you test out?" or "If you were that smart why didn't you just finish everything in a couple months?" But these are impossibilities in the current system.
The school system is akin to having a giant pile of rocks.
Which is a better use of your time if you're capable of building a crane:
A) You can either carry them one by one to where they need to go (finish hs)
B) You can build a crane that moves them faster (drop out and pursue more).
Agreed, but it still requires at least 35 hours a week of sitting in class.
I was pretty much this kid, or close to it, and to this day that statement is still one of the most valuable, harshest truths to me. So just challenge the kid to make it both work, run the company and finish high-school. If the kid is this smart he can do way better than running some VPS hosting company in the long run.
edit: I'm not from the US, but biscarg's comment sounds like it would be pretty good for the kid.