Do men usually keep bringing up stuff if it bothers them?

Do men normally keep bringing something up if it bothers them?
A guy I know introduces a female to us as the woman who was in love with his brother.
This young lady says that he always do that talk about her and his brother. Apparently a very long time ago these two were an item first but he was living with another female at the then so he was cheating.At one time I guess because of that situation they had to take a break.

The young man brother who is like 4 yrs younger took that opportunity to hit on the chic he was having sex with. This guy the one I know had no idea at the time but found out.
There was nothing he could do because he was in a relationship.The brother told this lady
the brother was mad at him because of it and she had no idea.Long story shorten long time ago. Now that yrs went on those two rekindled and whenever he sees someone and introduces her he refers to her as the one his brother was in love with he brings it up.

I am on here because yes I know him and I am asking because it is a message board. He ask us men and woman on job is it wrong of him doing that.