Your son probably wouldn't be interested in the romance section anyway, but many of the free romance books on Kobo are smut. I'm not sure how you feel about this. He'll probably gravitate to books of more interest to him anyway.
Probably best to download lots of books to Calibre - one set up for him - and let him choose what he wants from there.
By the age of twelve I think I was reading the Confessions books, such as Confessions of a Window Cleaner by Timothy Lea. They were circulated amongst the kids at school. Not recommended.
