How Can God Exist if We Cannot See Him?

My back yard

Recently a precocious grade-schooler asked me the question: how can God exist if we cannot see him? Here's my response.

1. Since God is, by definition, omnipresent (simultaneously present to all times and places) God cannot have a physical body as we have. That would limit God to spatial and temporal conditions. That is, because God is everywhere-present, it makes no sense for God to have the kind of physical body we have.
2. Because God does not have the kind of physical body we have, God cannot be seen as we see physical objects.
3. This fact of the non-physical nature of God has nothing to do with God's existence. That is, simply because God cannot be seen says nothing against the existence of God.
4. Perhaps the question should be stated: how can we know that God exists if we cannot see him? If that is the question then I would respond that it is possible to know that certain things exist even if cannot see them. We know that purely mental objects exist, but we do ot see them physically. Love exists, but we cannot see love. And, philosophically, some mathematicians believe that numbers (which of course cannot be seen) exist as abstract objects.
5. We are also told that one day we shall see God, so God is not in principle unseeable.

So I do not think that the current physical unseeability of God entails that God does not exist. We can, e.g., use the logic of inference to the best explanation and reason that God exists. See my post "Inference to the Best Explanation & the Fine-Tuning Argument."

Will my precocious grade school friend understand any of this? Probably I'd have to sit down with him and try to explain it more in his language!