I totally relate to your son's story. My brain of ten jumbles when typing and my left hand does what the right was supposed to do, flipping every other letter without realizing.
Growing up, I never showed my work and got docked for it. I learned to show my answer, but I showed to ways of solving the problem. When asked why, I stated because if I do it one way or the other, historically would get docked because it was not the way I was taught. If I show both ways, then I got it write and you see how I came to the solution. It was always double the work, but like your son, the argument was rewarding.
As far as English or literature, I avoided it like the plague.
Thank you for sharing this piece.