If my son or daughter had a chance to make hundreds of thousands of dollars before graduating high school, and high school was in the way, I'd tell them to drop out and make that money. They can ALWAYS go back for education if that opportunity evaporates. ALWAYS. In fact, if they get paid and flame out, then they can pay for a great college education to pursue their next dream.
Seriously, high school doesn't mean shit. College is a much more healthy atmosphere to get an education as compared to the the clique filled high schools.
Rather than trying to look at basketball as just a game, try to relate it to something that an average Joe would be doing. If your 16 year old son got a marketing business going and he was offered a contract to work for Nike for $350,000, would you stop him from taking the job because he hasn't graduated high school yet? Or would you say, "that would be a fucking disgrace to you and this family! You are not dropping out of high school to pursue a once in a lifetime business opportunity. You have to take the long, meaningless, and hard road to get to where you need to go because that will make you are real man!" Get the fuck out.