Originally Posted by elh0706
I think he just gets fed up with doing things someone else's way and just wants to do his thing for a while.

I wonder if this is part of her issue. Also, she is dyslexic and wasn't very interested in reading the "less interesting" books. Now that she has reached a certain of mastery, she enjoys reading on her own. Maybe she is frustrated by some of the foundational stuff that she needs to do on piano too?
Thanks for letting me think out loud about this.