You are crazy to not have a backup generator! It is an essential item to have!
You are crazy to not have a backup generator! It is an essential item to have!
Now I live in a single-family home and have an entire RV parked beside the house (with an on-board generator, and around 100 hours of fuel in the RV's gas tank to run it). I can run an extension cord to power the house furnace as needed, but unless it was below freezing and I was worried about the pipes freezing in the house, I'd probably just let the house stay dark and move into the RV during an extended power outage.
So I can confidently say "You are crazy to not have a backup Recreational Vehicle!". Maybe I should buy a travel trailer to back up the RV.
Might be easier to convince them if you shared the electricity . . .
Do not run a propane generator in or near your garage if it's attached to your home, since there's a serious risk of CO poisoning. It should be located as far away from the house as possible and away from windows and doors.
Prefarably at least 20 meters, especially if it is a gas-powered generator (OP mentioned theirs is propane, which is not quite as dangerous as gasoline).
Edit: I hope you have battery powered CO detectors on each floor and near the bedroom.