What Martha Mier and Dennis Alexander books are you using?
For getting into the classics, I would go to:
Classics for the Developing Pianist eds. Clarfield/Lehrer
Keys to Artistic Performance eds. Clarfield/Alexander
Keys to Stylistic Mastery eds. Clarfield/Alexander
Classics for the Developing Pianist has a new study guide to accompany books one and two. Books three through five are on the way.
I have a student who's enjoying Robert Vandall's Virtuosic Piano Solos. There's also Supplementary Solos (Book 2 at your student's level) from the Frances Clark library.
For future reference, you want to shoot for being out of the method books by the end of 2B, if not before. Also, spend some time finding ways to relate the music to his life, or bring it alive for him. Video game music is good, but also, for example, coming up with a story to accompany a sonatina, defining the dominant emotion of a piece and coming up with an appropriate memory from his life. Why should he care about this music? Do you play for him? It can be very motivating to hear what the finished product will be.