man, just read through some of this thread. This is sad news.
As for you getting in trouble, I dont think you would, but you should at least be aware of what you did and feel some responsibility. I once bought alcohol for a friend, and he just threw up a lot and I felt like it was all my fault.
Yeah, it was obviously not your fault and there's so many "what if I did/didn't" kind of situations to look at it as... but the fact you didn't buy alcohol with the intent to hurt someone, see someone drive drunk or any thing like that at least proves you are a decent guy and not a criminal. But from every drunken night, you gotta learn your lessons man. This may be a tough one. And you did not directly contribute to this accident, but some people would be in a lot of trouble over this.
sorry if I missed what some of this thread was about.. only read 1st and last page.