Honestly, the kid is 16. He doesn't have many carefree years left. He should enjoy being a kid. I would suggest that he focus on his studies and just being a kid. The better his grades and SAT scores the more ROI he can get in scholarships to get to a better school. This is the long play but i think its the best route. He will be working all his life. For now, go hang with your friends, holler at girls, relax.
If anything, instead of a job maybe just see if he can shadow some people at their jobs and get an idea of what they are like. That would also be very beneficial and might help him have a better idea what he wants to do down the road.