I liken the whole 607 vs 587 thing to December 25, is it really Christ's birthday or not?
You see, Jehovah's Witnesses love to tell people that 12-25 is NOT Christ's birthday and say, "Don't take our word for it, go to the library or the Internet and look it up yourself."
So why is it that if you tell a witness to not take your word for the whole 607 vs 587 and to look it up in the library or on the Internet, they don't follow the same reasoning and logic?
Just make them prove to you using sources other than the Watchtower publications. This uncle will probably try to use the Insite book and excerpts from the Kingdom Come publications. That's what one elder used on me, all Watchtower sources.