Ah, memories!
My sister, as a junior high teen, spent several evenings crying, after her three older, high school, brothers adamantly refused to let certain guys they knew from high school through the door.
"Not OUR sister is having anything to do with THAT _________! We had gym class with him, and KNOW what he's like!" or similar...and they didn't hesitate to tell Dad what they knew, either.
as much time as they spend quarreling, they really
do take care of each other, don't they?