If you search "universal sovereignty" here on JWN, you will find excellent discussions on the subject.
As BW said, there is no scriptural issue. It is only yet another tool the WT came up with to keep their worshippers thinking that their individual loyalty to the WT Corporation is somehow linked to some gameboard in the sky. If the JW has faith in that concept, there is no arguing with faith, since it is built on nothing but a belief.
What I have said to former friends in the past is I didn't understand why God had to prove anything to anybody, especially to a fallen angel or to a lowly human, and left it at that hoping that it will strike a cord with an inquiring mind.