Did he read the Ender series already? They are written at probably a middle-school age level, but I still to this day enjoy them.

LOTR and The Silmarillion are classics.

I just finished a series by David Moody. The first book is called Hater. It's got an apocalyptic, zombie vibe.

I don't read a lot of Sci-Fi so that's all I got.

Oh, also, DH likes the Terry Pratchett series.

~amy