Damon and Stefan calling each other brother constantly

I know the really popular scene in the first episode where Damon says “hi brother” is iconic, but upon rewatching I noticed that they constantly call each other brother. It feels unnatural, especially because imagine if Elena went around and said brother don’t do that, what is it gonna be brother or what are you doing here brother. It seems so unnecessary and cringe.

Is it because, it used to be common thing to do like a 100 years ago? And because their older it’s natural for them.

Edit:

Yeah I just looked it up and I was right. It used to be a very common way for sibling to refer to one another. I guess I just found it odd because it’s not really common anymore, but I can see why 100+ vampires would still do that.