J.C.
I bet his behavior during prayer time is a phase. If possible I would ignore it. He wants your attention. If he doesn't get it maybe the behavior will stop. I might also ask his teacher at church if he/she wouldn't mind talking about being quiet and respectful during prayer not only at church but at home too. I don't think he's too young to sit quietly for a minute. My two boys went through the same thing. They also want to speed through prayer. I understand your frustration! J.