Since he is plugged in, the converter should be providing 12 volt even if the batteries are weak so I thing it is something else. Since it is multiple things, my bet is on a fuse or 12v circuit breaker or bad connection. If you have your manual along, check to see if a wiring diagram is included and see if there is a common source for the 12v systems that are not working.
By the way, everyone should always carry the appropriate manuals in the coach as they don't do any good while traveling when the manuals are at home. If the manual doesn't include a wiring diagram, get one and put it with the manual. I recently had a question while in Canada, checked the manual on procedure, easily resolved the issue and continued on.