I quite liked Lloyd Alexander's Chronicles of Prydain series. The first of the five standalone books is The Book of Three. It clearly YA fare, but the writing and story are both good.
If you think he'd enjoy something a bit more intellectually quirky and humorous, there's always Terry Pratchett's vast collection of Discworld novels. Good starting points there might be Reaper Man, Men at Arms, or Going Postal.
My favorite urban fantasy series is The Dresden Files by Jim Butcher. It's not what I would call graphically sexual although there is some sexuality. I'd be more concerned that it's violent and somewhat dark. It's among the best stuff being written today, though, and I really do mean to put an actual rec in this group sometime. The first book is Storm Front.