Hey there Parse, so it sounds like your friend is a victim of the system where anyone that was in the area is automatically assumed to condone to a crime. Allow me to try and help, hile this is my personal opinion it comes from heavy experience. The stress of an accusation is objectively one of the most stressful things a man or woman can experience serious issues like depression, anxiety, acute stress disorder, and acute adjustment disorder to name a few. If your friend hasn't already spoken to a detective I would stress for him to not, until a lawyer is present. Detectives, NCIS, FBI, any criminal investigators are not there to help you and are certainly not there to prove you or your friend is innocent. There have been many cases where woman and men give their statements only to have their words twisted. As far as the stress is concerned it is indeed very traumatic. There is a good book called "The Happiness Trap," that helps its readers focus on the positive things in life. All too often when people have something incredibly stressful and negative go on in their life they develop a cynical and hurtful view of society. This book will help aim to counter the way you/your friend thinks. All I can say is that the truth will eventually show itself, if he/she buy alcohol for this person and just happened to be there, then there is no legal reason why they should face any repercussions. Hope this helped, good luck!
-Eric