All the best to your Mom, hope she has a speedy recovery. Now some tips. You can help the fridge to stay cold during these hot days by using blue ice. Freeze it in your home Freezer and then put it in your lower unit to absorb the heat when you are trying to get things cold. Always load your fridge with ONLY COLD stuff pre-cooled from your house fridge. Add drinks such as cans a few at a time. Don't put a warm 6 pack into the fridge all at once. When you shop for supplies, try to get things from the chilled store shelves only. Try to always park the unit with the fridge side in the shade. Open and close the door as quickly as possible. I have an ice tray which gets frozen each night and spends the afternoon in the lower unit. I put it back in the freezer at night and by morning it is ice again. Make sure your burner assembly on the back is not partially blocked by rust flakes from the chimney. 1 small screw can be removed and the little gas burner can be inspected and blown clear if needed, just always remember to put the cover back over the inspection hole or the unit can be affected by wind. It should cool better on gas than on AC.
On the shut-off switch, you are operating a small solenoid switch, so push the OFF side and hold it for a few seconds. The light should go out gradually. If you just hit the switch and let up, sometimes they will not disconnect. Never try to shut off the house battery while the truck is running, you can confuse the logic circuit.Try it.