Anyone read The Dark Tower series by Stephen King? I saw the trailer for the movie and it looks interesting and looks appropriate for my son's age. I can get $5 off the first book in the Google Play Books app. It is a family library one so it can be shared by like 5 family members.
Only if you are OK with violence, vulgarity and sexual content at that age. Like letting him read the George, R,R, Martin books.
Otherwise a good series, the earlier books in the series was the best, then the plot seemed to trail off.
If young adult fantasy,
Robert Jordan - "Wheel of Time" series spans like 14 books.
Le Guin - Wizard of Earth Sea series
Otherwise college level,
Herman Melville - Billy Bud, Moby Dick
Hemingway - Old Man and the Sea
Joseph Conrad - The Heart of Darkness , Apocalypse Now was adapted from it. very dark novel