I'll just review the entire story, rather than go chapter by chapter.
I remember way back when that the very first piece of gay fiction I ever read on the internet was a kidnap story (was on ASSGM, I think). And I literally could not put the "book" down. So when I learned that Forever Boy was also a kidnap story, I was intrigued.
FB is a quick read, but it never feels rushed. There is a clear beginning, middle, and end. Yes, the subject matter is a bit disturbing, but one must remember that it is a work of fiction. No minors are actually harmed.
I guess what I'm trying to say is that those of us who are in a consensual sex relationship find the fantasy of "forced sex" tittilating and erotic. We like to explore that "dark" side that resides within our inner souls. For example, I enjoy watching L&O SVU, but it would never compel me to actually go out and rape a woman.