Brother Manipulates Girls With "The Offer"

Side 1 says... My brother always finds a way into every single single girl he knows. Like clockwork, he pounces on them in their vulnerable state after a break up or just asks them for casual sex while they are in between relationships. And I mean he's blunt about it. His line is "Offer: Sex." to the question on what do you want to do. He says it joking but serious.

I guess it's fine when girls give into this but he knows girls are more emotional and hold onto feelings after they sleep with someone more than guys do. He uses this against them all. Now once he has at least 2 he's sleeping with at once he'll play them off one another or, since their original agreement was casual sex with no ties, he waits until they are starting to date someone else and then he introduces the two girls to each other explaining he's having sex with the one that's not beginning to date. This makes the girl dating jealous and he works his way back into that girl's bed while he's still doing the other girl! Every time it works. There's only been 1 he hasn't got it to work with.

He thinks it's a game and it's their fault but I think he's just using these girls and playing with their emotions. He should let them be happy if they are finding someone else interesting but he ruins each new relationship they try to start. He just did this to one of my friends who stopped talking to me because she chose him casually and the new guy came but she went back to my brother. I told her the whole game but he already hooked her. It's disgusting.

He just doesn't see how it's wrong. I can't stop him from doing it. I just want him to admit it's wrong of him to do that to all the girls in his life.