I bet he can actually read. Of course, I am biased by my own experiences.
I was accused of memorizing books when I could definitely read very young, between 3-4 years old. I remember being angry about that. (One of my earliest memories is being incensed at adults underestimating me.) I could read fine. To prove I could actually read, I picked up one of my grandfather’s electrical engineering books and started reading it aloud. There were some words I didn’t yet know, but I had no problem with most of it.
That shut ’em up. For a little while, anyway.