Just saw the movie and looked up the 2006 news articles. There were 4 boys in the car along with Luke Abbate. They were injured, but it does not appear that they died from their injuries. Their names are posted out there, but I will not name them here.
I will post the actual report here... http://www.georgialax.com/abbateinformation.html this answers the question in depth.
Other people asked questions on various topics, and are still waiting for answer. Would be great if you can take a sec and answer them