I'm reminded of the argument I heard from one kid that if eating junk food was "bad" it wouldn't satisfy their hunger and be so tasty.
The core of that argument, like this one, is that the fundamental assumptions about what the activity is providing are incorrect, and that leads to poor reasoning about the problem.
In my case the young man had made assumptions about signalling his body gave him with regard to being hungry or not as a signal of quality and/or acceptability. In the author's case the young man has conflated the value of education with the value of earning a living.
I agree with others here that if he is "that smart" he should be able to just finish up the high school curriculum and get that out of the way. I'd certainly consider home schooling him, since his business is so successful he should be able to hire himself an individual tutor, get the basics covered, get certified, and then get his degree. These folks typically deal with kids of movie stars or executives who are travelling a lot but they are out there.
If the kid is smart, and you want to reason with them, do it at the company level which he has so much of his identity invested in.
What is his gross margin? EIBTA? Net income? What are the strengths, weaknesse, opportunities, and threats for his business? What happens if Notch decides to cut off folks like him? What's the next step in his life? And the one after that. When he's dead what does his obituary say, "Man he ran the best Minecraft servers." ? He has shown that he can create a business, that is great, but does he have the stones to make bigger businesses? Or is he strictly small time, the 21st century equivalent of the guy who owns and runs the gas station on the corner his whole life? Who are his heroes? His anti-heroes?
Clearly he has had success in his goals, but he doesn't know what he doesn't know. The goal of an education is to give you the tools to attack the problem of developing knowledge when you are confronted with a lack and a need to know. Its artificial in the education system (do you really need to know about ancient history?) but the tools and techniques are widely applicable.