Aristotle and Dante Discover the Secrets of the Universe by Benjamin Alire Saenz (2012)
There is so much going on this book. One of the major events was a serious accident that was a catalyst in bringing Ari and Dante closer together, and the repercussions played out throughout the novel. Both characters are Mexican-American and they live in El Paso, which is pretty unusual and underrepresented in literature. Ari's parents were emotionally inaccessible in some ways, and didn't understand how much it hurt Ari that they refused to tell him anything about his brother, yet they were decent people who obviously cared and wanted to be supportive of him. (And I loved that both characters had good parents who have prominent roles in the story.) I don't think it's a spoiler to say that sexuality is one of the main issues in this book. Partway through it becomes clear that Dante is gay, and I thought this theme was handled in a way that was both subtle and realistic.
It's hard to do it justice, and I'm really failing, so you may just need to take my word for it that this is a great book. The writing is sophisticated yet still very accessible. I began reading it early one evening and finished the next morning. I never read that quickly, but I just flew through this book. I didn't want to put it down.
I started looking to see if the author has written anything else and it turns out that ALL of his YA books have won awards or been listed among top books for teens. He is obviously very talented and I hope to read more of his work. I wholeheartedly recommend this book to anyone who likes young adult fiction, or really anyone who just likes good books.