Bob wrote:

I agree that it could be a dangerous situation, but I think he should call
someone ASAP. It would be terrible if something happened, especially if it
takes a few days for him to get around to doing it, and someone in his
family fails to wake up one morning.


SNIP


That's a fair point indeed.
I'll amend my advice to: "Shut off the gas line to the heater ... now.
Jim