Your son is asking great questions. His interpretation, at least in some respects, is a relatively accurate reflection of what the text actually says. As Catholics, we theologize the text and add theological concepts like original sin, the serpent being Satan, etc.
Read critically, the story says this:
God creates Adam and Eve to till and keep the earth. He gives them permission to eat from every tree in the garden except for the tree of knowledge of good and evil, or else they will die. The serpent does not deceive them. The serpent merely tells them what is apparently true: they will not die (they don’t unless we add a spiritual interpretation), and if they eat from the tree of knowledge of good and evil they will become like gods. At the time of the writing, the characteristics of a god were twofold. First, gods lived forever (represented by the tree of life). Second, gods had special knowledge (represented by the tree of knowledge of good and evil). The God in the story is a jealous God, so since Adam and Eve ate from the tree of knowledge of good and evil, God, in order to maintain his uniqueness, banished them from the garden to guard the tree of life from them in order to protect God’s uniqueness.
From this perspective, Adam and Eve did not necessarily get a raw deal since they were not tricked by the serpent even though Eve claims she was. Read critically, Eve is trying to pass the blame to the serpent, just as Adam tries to place the blame on Eve. However, the God in this story is a jealous God who is trying to preserve God’s uniqueness. The moral of the story, like most stories in the Old Testament, is this: humans are not gods, and when humans try to make themselves like gods, they suffer devastating consequences. It is important to note, however, that the tendency to protect God’s benevolence in these Old Testament stories often leads individuals to read more into the stories than what is really there. This story is not Greek, so the Greek concepts of God adopted later would not have been assumed by the author.
Lastly, it is important to note that I am not saying that the traditional Catholic interpretation is false. I am merely pointing out that the story, read critically, does not fully support the Catholic interpretation. One must read the story in light of Catholic doctrine in order to come to our doctrinal conclusions. Neither interpretation is false. Instead, the same story is just interpreted using different hermeneutics or with different hermeneutical keys.
