Was my behavior right or wrong when I raised my voice in defense of my friend and his father after they were verbally abused by an older man, and what is the ideal course of action in such situations involving injustice or accusation from an older person?

There is nothing upon you, Allah willing, for you have enjoined good and forbidden evil with your tongue, without indecency. As for the one who wronged you and is older than you, you have the right to seek justice from him commensurate with the wrong he inflicted. However, it is better to forgive, based on the Almighty's saying: "But indeed, if any show patience and forgive, that would be an affair of great resolution." (Quran 42:43). The verses mention three levels: seeking justice from the oppressor without transgression, responding to evil with good, and patience, forgiveness, and pardon, which is the highest level.