What would be the point of going and communicating with new schools? To let them know you'd love for them to be a backup option? If he doesn't get in he can always apply to other schools, explain the situation and show up the first day of tryouts. If you're good enough they'll keep you, they don't have scholarship guys to account for. Recruiting means the least at the D3 level, your game determines your role, not so much the commitment you made.
That being said, unless travel and all that is already paid for I would just skip it. No sense in reaching out to new schools now. We're 5 weeks out from ED applications being due and realistically they're all done 2 weeks prior. Part of committing to a school is being able to get in academically. If the coach can't guarantee admission then it probably isn't a school he should be committing to.