Joliette, I'm afraid you're wrong. Jehovah sometimes decides to change his mind. For a while he thought "higher authorities" were governments, then he decided they weren't, and let the faithful and discreet slave know this. Then he thought again and had to let the FDS know that he'd gone back to square one.
He has also rethought the concepts of "generation", blood fractions, oral sex, alternative service for conscription, the last days, the separating of sheep and goats, the shutoff date for the heavenly calling ... and, to his great credit, has kept the slave class informed of his adjusted thoughts.
He WAS contemplating resetting the last days to begin in 1957, but rethought that; he let slip to SOME of the anointed a thought that the "other sheep" were just the Gentiles, but pulled back on that one and was a bit annoyed that those anointed went ahead and talked about it.
Look, Jehovah does change his mind, OK? And if he decides those immutable laws of science need to bend a bit when he wants, he'll do it. Bugger gravity. Bugger the consistency of time. Bugger tectonic plates. Bugger the dietary habits of carnivores. Bugger the consequences of, say, falling from a great height or swallowing arsenic in the new system.
I'm with your mum on this one. Like Roger Waters says, What God wants, God gets.