That's just a cryin shame man.
I learned the exact same lesson when I was in high school. I played trumpet, and I was pretty damned good at it for a high school kid. There was a soloist competition for players of the various musical instruments. I played for the judges, and got very high marks. Then this girl, a very good looking girl, from another school, played her trumpet right after I did. She sounded awful. Missed a lot of notes, played flat, just sounded terrible. At that point I just felt sorry for her.
She won. I got second. I was pissed. The entire audience was shocked. Most thought that she shouldn't have even been in the competition.
But I did find out later that she had other 'hidden' talents that pleased those judges.
But that was back in the 70's when that sort of thing wasn't as carefully scrutinized by school administrators and law enforcement types.
I sometimes wonder where that girl is today.
Congress on her back? The senate on her back? Whitehouse on her back? Who knows?
Tell your son he's the real winner here, because he did it with his own hands, and has a future. Whereas, that other kid that won with the store bought tinker toy, will never have a chance to learn anything on his own. He's pretty much doomed.