Watt and volt are two different measures for electricity. Also your fridge will not work when hooked up to a car battery for many other technical reasons, including differ t voltages, and current types (AC/CD, not the band)
That vehicle isn’t using a traditional 12v car battery for that. Also the point t is you can’t connect a car battery to a fridge and expect it to work.
The only way the “uncle” is correct and the only way a 12VDC battery is getting connected to a regular, 120VAC refrigerator, yes. And what most inverters run off of.