To act or not to act

November 17, a Thursday my brother had just turned nineteen and wanted to go to a club in Hamilton to drink and have a good time. We had planned that I would drive him and his friends to this club and pick them up. On the door they had a sign saying the night will go till two A.M., but the music shut off at about 12:45. To my brother this was a waste of his money and he wanted to make a point by attempting to get his money back. He tried everything he could, talked to people who just told him to talk to other people, this turned into yelling and one of the younger managers completely disagreed with him. When my brother finally stepped outside and we started walking to my car this manager came out and told my brother to take the money from him by fighting him. My brother didn't want to fight him because there was no point it was over twenty dollars and my brother was a relaxed person. This guy was about the same build and height as my brother and wanted to fight him over twenty dollars. This whole time i wanted to leave and not have this happen, ending the night that early wasn't nice of them but i didn't feel it was necessary for my brother to act the way he did. As these two were face to face i wanted and thought about acting to split them apart but couldn't, I guess i felt i would get involved in it all if i stepped in but I also knew my brother could handle himself no problem. They did end up fighting, it wasn't long and my brother didn't get a scratch, he gave the other guy a bloody nose. I should have acted and i still think about it even though the conflict was not at large or had any serious risk.