Definition: Given a real-life anecdote of a complex ethical situation, generate a suitable title that describes the main event/root cause of the situation. Imagine that the given text is a social media post, and you have to write the title of the post, so the users can decide to read the main text or not.
Input: I (female/26) am visiting my brother on vacation for the weekend with a female friend of mine. We're staying in the living room at his apartment with his room about 10 feet from us. My brother does not have a girlfriend and has been open about his sex life/hookups. It's our last night here and he turns to us around 9pm and says I'm have a "friend" over tonight. Which clearly means a girl.

So, I then look at him and then freak the fuck out. "NO YOU'RE NOT. So you can hook up while my friend and I are in the room next to you?" He tells me they're not going to do anything and I'm assuming things, then calls me a fucking bitch for saying that and that I can't tell him who he's having over. First of all what male aged ~24 has a sleepover with a girl he's not dating and it's PG. He's told us she's his booty call for god sake.

I know I didn't handle it well. I was in complete shock and disgusted. I'm his sister! WTF! 

She's not coming over anymore thank god... But there's hostility in the air now at the apt. Whatever. 

Do dudes think this is ok?
Am I the asshole for telling him who he can't have someone over in his own house or is that just plain wrong?

staying @ bros apartment for the night and he says his booty call is coming over. I tell him no