Is he a coach?

[Adam]

I don't care if there's seating or not.
In this case, he had started off on the bench as a coach. He's a coach.
Also, anyone on the sidelines who's telling the offense what play to run is a coach. I'm not talking about cheering or encouraging, or even yelling, "shoot that!" If he's yelling plays and the kids are listening (assuming I can tell), he's a coach.
Coaches sit on the bench.

If I have any doubt, I'll inform him that if he continues to coach the kids from the stands, he's going to be removed from the gym. The other option is a T for leaving the coaches box. I'd want to avoid that if I wasn't sure it was a coach.
However, in this case, it was a coach who started off on the bench. I'd give him one warning to get back to the bench (since we're talking about a 12 year old league.)