It happened in 1991 when they were both 18. She has forgiven him and he offered an actual apology. (none of this: If I offended anyone BS).
If other women come forward that he was abusive, then I reserve the right to change my mind based on new information.
If the mom was so concerned she could have notified US Soccer long ago since he has been the coach for a while. The timing of this certainly seems more about being vindictive than trying to keep a "woman abuser" away from the players.
US Soccer might not retain him. If they base that off performance then fine. If this allegation plays any role it is a pitiful situation.