I bet, but that's just my intuition, that being a linguist and an academic, again just by the very practice of having to study the tool that is language and writing about it, makes it a very different situation compared to "most people" who have never written essays since high school and I possess only a very basic understanding of grammar, etymology, etc. I bet the very topic and context makes his situation not normal.

That does not mean he does not have cognitive capacities that most people might not have, but, again the practice itself most likely changed him, not solely "selected" him for the practice.