As a Dad of HS soph and a coach, I would recommend that he do the same. Speak to coach. If coach will not give him freedom to do some work away from team (uncommon in my experience), then work around the school workouts and don't double up on anything. My son trains outside of school but his trainer does a great job of asking what he has done and then works around it. Experience has been great so far. Trust me, he could experience the same thing in college. I have talked with many college athletes when they return home who are not happy with their training programs and complain that our HS S&C program is better then college program.