the DA has nothing to do with what claims you might have against the school. Yes, the DA does control who is prosecuted but often times, in situations such as this, agreements can sometimes cause the DA to not prosecute for such a minimal charge.
The fact the judge questioned prosecution, it would appear this is being driven by somebody and in college towns, what the college wants often means a lot.
So, any agreement would have to be an agreement between the school, your son, and the DA. Your son and the school for any release of claims and between the school and the DA for the school not wanting this prosecuted. There are never any promises in a situation such as this and the assistance of a lawyer might be of great help.
as long as the coaches actions were within actions allowed by the school, there is nothing improper with what the coach did. Multiple punishments only count in criminal court. The courts impose criminal charges and punishment for the criminal act. The school has all rights to impose punishment for actions at or involving the school.

