The refrigerator and a/c should still work on shore power. You can check them out that way. I don't see why the generator running out of gas would make them not work. They would just shut down, just as they would, if the rig was unplugged, or there was a power failure.
I am with you, it doesn't sound logical. Maybe if the rest of the unit suits you, you can make an offer that would offset the cost of a new a/c and fridge (Two of the most expensive things)
Rving, and fixing them since 1968
Don't Drink and Drive, EVER!!