Answer to Question 1
Answer: A culture of honor is a culture in which protecting one's reputation (honor) is vital. It emerged in the southeastern and western U.S. among people who herded cattle for a living. Their honor, or reputation, was important in protecting their cattle from thieves. In a culture of honor, aggression is considered an appropriate response to being insulted. Thus, even today, some southerners and westerners may be more easily provoked to aggression if they are personally insulted.
Answer to Question 2
Answer: Alcohol serves as a disinhibitor. That is, alcohol lowers the friend's inhibitions, and thus makes the friend louder and less reserved. In addition, alcohol interferes with processing of information, making the friend less thoughtful and also more likely to miss subtle situational cues, such as the slight nudge, that could prevent aggression. In addition, according to the think-drink effect, your friend's behavior may be the result of behaving as he/she expects a drinker to behave.