Related Experience;
Basically what happened is my mom was studying with my 9 year old sibling and they were talking about the paradise. My sibling then proceeded to ask, in a clearly joking way, "What if Jehovah was tricking us and we don't go to paradise?" He was laughing and clearly just asked it to be antagonistic but my mom took it so seriously.
She, of course, got very defensive and explained the whole "Jehovah loves us and won't trick us" thing. My brother just kept pushing and asked, "What if he was lying?" This prompted the age old "Jehovah cannot lie. Just like no matter what we do we cannot fly, Jehovah cannot lie."
The last push was my brother asking, "What if he's lying about not being able to lie?" This just set off my mom into fear mongering mode and she basically threatened him with getting his "eyes picked out by ravens" for being rebellious and "saying bad things" about Jehovah.
A bit much for something that was clearly a joke, as I could tell from his incessant laughter that got harder with each antagonistic question. And her reaction was clearly what he was going for, up until the fear mongering part at least.
He's still clearly believes in Jehovah, which is understandable because its all he knows, but if he can realize that people can lie about not being liars and then apply that to God, then who knows when he gets older. He might view it as a joke now, but I'm sure his mind can connect the dots when he's older.
I was also skeptical about certain things when I was his age, and younger. Like I'd always think, why do we say everything *must* have a creator but Jehovah just *existed* forever before even making us. It was quite the mindfuck to just have accepted that this one entity existed just because while simultaneously being told that things cannot exist without a creator. I know both things are very simple conclusions anyone could come to, but it's quite impressive to me since the cult heavily ingrains in us that skepticism is basically apostasy, to the point where adults don't even like to entertain past a certain point of skepticism. If you're not satisfied by the first answer to your question and ask more, then you'll be looked at funny.
But look at me now, from a young skeptic to a filthy apostate lmao. I'm sure he's gonna be able to figure out Watchtower is bullshit eventually.