First post, new member... I am currently taking intro to criminal justice and we had a recent discussion that was very similar to this. My professor is a retired police officer. He said that whomever bought the alcohol is completely accountable for anything that happens due to intoxication by that alcohol. At least in the case of parents buying it for minors. The fact that he was 21 might make a small difference, but i'll have to check on that. I'll ask my professor tomorrow and see what he says.
Sorry too man...i always hated waiting for the police to knock on my door...worst feeling ever...