Welcome to iRV2 .
Sorry your first post is about problems .
First could you add some info about your coach ;
Chassis manufacturer? Engine ?
During the time at home was the coach plugged in ?
When boon docking , was it JUST the chassis batteries that were dead ?
JMHO: If the battery banks were inter-connected; allowing the coach batteries to start the coach ; even with the chassis batteries disconnected. Then any draw that would kill the chassis batteries would kill the coach battery while boon docking.