You didn't tell us anything about the coach, year, make, model or type, so we can only guess about it. Rarely, though, does a motorhome have a separate generator battery - it starts of either the house or chassis battery. Separate genset batteries went out of style 20+ years ago. It appears you have enough battery power to start the genset, so that is good news. Running the genset powers the house charging system too.
The emergency start function also needs 12v power (Catchh-22!) to operate the solenoid, so if both your batteries are near dead, it may not work. More often, though, something has failed in that circuit but was undetected until it was needed. Loose wire, bad solenoid, bad switch, etc..
Scott gave good advice - get the chassis battery working (probably just replace it) and then investigate the other problem.