If he is released, then he will not have to sit out a year. If the school chooses not to release him, then he must sit out one year before returning to play. It should not be a problem if, as you say, he may not be offered his ship next year.
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 .