Rob - depends on what you want - gritty and real or more uplifting and encouraging.
the former would include books by Paul Zindel, S. E. Hinton, Gary Paulsen and Robert Cormier. these deal with boys in difficult situations. the more pleasant ones would include classics like C.S.Lewis' Chronicles of Narnia, Tolkein's works, Madeline l'Engle, and others. a visit to a bookstore or library might also help - you could ask a librarian or clerk for suggestions and browse the YA - young adult or youth fiction section and see what might be appropriate. much will depend upon the boy's reading level - Tolkein is more difficult than Lewis.
when i was that age i was reading Mark Twain, Robert Louis Stevenson and Charles Dickens (as well as Hardy Boys!) among my favorites are still Huckleberry Finn, Oliver Twist and Kidnapped.
i don't know of anything written for kids that specifically tackles the topic of CSA. what helped me was just generally recognizing good and bad role models and seeing the results of decisions and circumstances in characters' lives in the narrative.
As my life goes on I believe somehow something's changed
Something deep inside...
I've been searchin so long to find an answer
Now I know my life has meaning
Now I see myself as I am, feeling very free...
When my tears have come to an end I will understand
What I left behind: a part of me. Chicago