He may have a 30 amp coach but that's a 50 amp generator
His problem is with one of 3 things
The intelletec controller is not sensing the generator properly (Since I don't know how it senses generator power I can't say more about that)
THe Auto Transfer switch is the wrong one or wired improperly
A Switch is set improperly
When running on Generator one of the A/C's is supposed to be powered by the 20 amp breaker on the Genny. Directly, Via the Auto T ransfer switch IT does not
It may be other loads (like water heater) causing the sheding as well I do not know.