I think he HAS to do that. Not overkill at all. Coaches need to know a kid is really interested because there are plenty of other quality kids sending stuff in on their own.
When you block a person, they can no longer invite you to a private message or post to your profile wall. Replies and comments they make will be collapsed/hidden by default. Finally, you'll never receive email notifications about content they create or likes they designate for your content.
Note: if you proceed, you will no longer be following .