He is stuck on Adam and Eve being very innocent like a toddler and how then unfair God was.
He does have high functioning autism and tends to have trouble with the abstract concepts of the Christian religion.
He my be empathizing with Adam and Eve, and worried they, like himself, had difficulty discern others intentions and getting unfairly in trouble for it. Addressing his concerns from this angle may help.
Background on the rest of his question:
God didn’t give us free will, the devil did because the tree of knowledge of good and evil is the only reason why human beings know right from wrong. It is because of what the devil did in the garden that we have more responsibility than an animal does. So the devil gave us free will not God.
The Tree of Knowledge nothing at all!
Adam and Eve were created in the image of God and full of Grace (just as the Blessed Mother!). The serpent told the women that it would make them like God, and she envied God, believing he was denying them something.
So she and her husband ate of the fruit. Nothing happened. The snake lied. They felt deep, crippling shame, and hid from the Lord. They covered their bodies to avoid looking at his image.
When they broke God’s one explicit law, they already new it was wrong to do so. They did not need the tree to learn that. They knew they were created in God image, but did not share God’s nature; they sought to change their nature by stealing God’s knowledge by disobeying him. They innately new this to be wrong.
God had given them everything,
and they did not trust him. God promised if they ate of the tree, they would die - God did not lie.