Can we ask him that, what would be his rationale to say that?

Any rational human being is capable of articulating truth. And I assume your friend is, this is why we should asked for his rationale.

Precisely. This is why I said "any"... not all humans are rational.

I am not child expert and I cannot assert regarding their rationality. But I know children are inconsistent decision makers. However, a child at early age is not strong enough to resist or oppose the will of his parents - customs and upbringing.

We have discussed this with you before here that every child is born in a state Fitra. That means, every baby when born has recognition of God. As a part of their nature, a Creator imprinted in the soul. It is the parents who make that child a Jew or a Christian or a Polytheist or Atheist. Naturally, a child submits to physical laws of universe, the soul submits naturally to the fact that God is his Lord and Creator. But, the parents try to make him follow their own way (read religion). And a child at that early age is not strong enough to resist or oppose the will of his parents - customs and upbringing.

I did not say rationality equates opposition.

You asked about children. You see, every child is born in a state Fitra. It is the parents who make that child a Jew or a Christian or a Polytheist or Atheist and a child gets brainwashed into the customs and upbringing of the environment.

Now when you reach adulthood, you need to use your mind, INVESTIGATE, why should you be blind to something that might have impact on your life and come into your own conclusion.

This applies to almost everything. From career, to matters of faith. As an adult you need to begin to rationalize your choices in life.