[Adam]

Tell them if they don’t get their heads out of their collective azzes, you'll bring in volunteer parents.
Tell them to eat before they come to the game so they don’t have to swallow their whistles during the game.
If you think the pressure is too much for them, have a group therapy session and discuss empathy or something.

Seriously, maybe get out there and ref a game with each of them. Do it three whistle, if you want. Get together with them during timeouts and intermissions to discuss individual plays. It might be that officiating isn't for them, who knows.