Oh my god, I love this because he is experiencing a legitimate psychological trauma response called regression. Regression is an unconscious defense mechanism, which causes the temporary or long-term reversion of the ego to an earlier stage of development (instead of handling unacceptable impulses in a more adult manner). In other words, you unconsciously revert, or go back to, a younger mentality (often childlike) and will usually exhibit behaviors associated with such a mentality. And so, by regressing back to our younger mentality, it is quite possible we unconsciously blocked out most of our traumatic memories in order to protect ourselves while we are in such a vulnerable state.
