Congrats on both your kids even being in a position to be doing these things! It really hit my D18 hard this year, when all the people her age are showing their accomplishments (and getting scholarships for them), and she has nothing to show for it. She pushes herself studywise, but wouldn't do sports, dropped out of choir, too clumsy for dance (though she did it for 3 years), just never wanted to belong to anything like that. Now it's hurting her.

That said...
As for S14, why not just let him vegetate, hang out with friends, read books, go hiking, play street ball, whatever he feels like? I truly think that we put too much onus on kids to be always performing and achieving, and that's why kids are so stressed out these days. They never have quiet time. They never spend two hours straight with no music, tv, games, or programmed activity.