What would you do??

Here is the situation. My friend wanted to downsize and be able to boondock camp so he went to a dealer and was sold a new Cardinal with a residential refrigerator, a 5K generator and 1-12v battery. He's going to pick it up in a week. I know there are all sorts of issues here. He didn't ask me anything and I'm not volunteering anything but know I will eventually be involved and will want to help. He will not want to spend much money. How's the best way to modify the rig so he can dry camp without running the generator all night? Oh, he also has a CPAP machine.