Jehovah's Witnesses live in a childish fantasy.
Since when did Jehovah do anything at all? How can anything be attributed solely to Jehovah's doing? There is no evidence for any deity let alone Jehovah, therefore he and his exploits live only in the realm of fairy tales.
The only evidence for YHVH is in the evolution of an ox-headed idol the Hebrews inherited from their Phoenician neighbours way back in the Bronze Age. Who would want to "draw close" to this monster as your sister is recommending? Jehovah hates everything the Hebrews hated back then. This god's 'love' for his devotees involved killing all those who disagreed with him including smashing the heads in of all the children who were not his followers. It's far worse than childish -- worshipping Jehovah was routinely evil exactly like the exploits of other pagan gods at the time. In Isaiah 45 v7 (and elsewhere) God says he does good and evil. He is a jealous god with a short temper, completely fabricated from the worst qualities of fanatical nationalist zealots. Have nothing to do with it.
Help your poor deluded sister with the milk of human kindness and fellow feeling, help her to escape the madness which comes from slavish obedience to this crackpot religion.