Most AAU programs around here will not expect any kid still playing in HS playoffs to attend games scheduled for the same time. Besides, unless those said college coaches are expecting the kid at the tournament through previous communication, I think he can miss one tournament. At which point those same coaches would probably pay far more attention, at later tourneys, to a kid who contacted them explaining it was important for him to be with his HS team through the playoffs and he greatly apologizes if they were there to see him. OR if there had been no prior communication,,, to send a note stating that he really wanted to play in front of them and ask if there are other tourney's/showcases/camps they planned to attend in the future.
Dependability is a huge consideration for any coach, especially college. Whether that is game related or personality.