Seen,
Another example of high school coaching mopery.
Just as your son has one senior season, so, too, he has one opportunity to see and be on a college campus (or more than one).
I would go to the principal and the AD (at a simultaneous meeting with the two of them so they wouldn't "forget what they said", if you were to meet with them independently), after I had exhausted all attempts to reach some compromise with the coach.
Can't imagine a single program in Chicagoland that would require game "attendance" to a pitcher (who, if he receives some baseball scholarship assistance) who can only bring honors to the high school program.