Funny how many people in their 50s think they’re old. Maybe 57 was old in 1821.
It’s not old in 2021.
Let me explain. Early on, “bro” mostly referred to a male friend rather than just another man. Later, “bro” became associated with young men who spent time partying with others like themselves. Some identifiy the term "bro" as the one "defining feature" of the changing cultural attributes of manhood.
Oxford Dictionaries identify bros metonymously as those who themselves use the word to refer to others, such as in the example of "don’t tase me bro” in which the taserer is not a bro, but the tased is. The subculture is not defined consistently or concretely, but refers to a type of "fratty masculinity.”
In most cases, the word “bro” used by middle-aged men are those having a hard time adjusting to being middle aged men. Nope it’s East coast as well.