It may not be exactly what you're looking for, actually it might be completely unhelpful, but the first book that popped into my mind was "How I Learned to Snap" by Kirk Read.
Amazon.com had this to say about the book: "With bold Southern humor, journalist and performer Kirk Read takes readers on a guided tour of his precocious and courageous adolescence. Recalling his years as an openly gay high school student, Read describes how he navigated the hallways with his sense of humor and dignity intact. He fondly recalls his initiations into sex, drugs, and rock 'n' roll, as well as his "shy as neon" acts of rabble rousing during high school. How I Learned to Snap is a refreshingly victim-free story in which queer teenagers are creative, resilient, and ultimately heroic."
At very least, I enjoyed it.
I also agree with Graeme that just because he's gay doesn't mean that he has be ridiculously, flamboyantly GAY. Hopefully he'll come to terms with himself and eventually be comfortable in his own skin being himself, whoever it may be.