I am so glad that your son is not excepting thing at face value. That is so great. It is always a good thing to ask questions. Continue questioning thing!
But you know what? This is one of those subjects that actually make sense to me. I don't conside it JW' doctrine. But part of the bible. My take on this is, and you certainly don't have to agree with me is as followed.
Let's say God zaps Satan, Adam and Eve. So there is no one to question the fact that we can't make it without God. Then what happens if he makes two more people and they start saying, "No I don't want to do it your way. I want to find out if I can do it on my own." Does god zap them and so forth and so on. I know it sounds unfair to have satans influences. But I don't want to serve a god that won't allow us a second chance. Or even the chance to find out if we can make it on our own.
Hey we all came from a religion that says,"Do it my way or else." Well none of us liked that very much, that's why we are here. So a God that rules so we can't make decisions for ourselves, doesn't sound any better. That's the way I look at. But like I sayed that only my take on it. Doesn't make it right.