Propane is a very dangerous fuel.
It is even worse than natural gas because propane is heavier than air and sinks to any low spots and stays.
At least natural gas floats up and away.

There are reams of safety information and advice everywhere about propane and we still have people blow themselves up with it every year.
In construction we don't even allow the stuff inside winter enclosures with heaters and we apply distance limits to buildings for it.

The valve on the bottle does not even need to fail for a leak to happen. It could be from a blown out pilot light or from an appliance valve being left on.

Oddly enough we consider it safe enough to use on forklifts in warehouses.

The grandfather broke a couple of extra rules too.
Propane stoves are not meant to be used inside. The same with the coleman fuel stoves.