My Yandere Sister loves me too much!

My little brother's coworkers are a bad influence on him! Always inviting him to mixers and telling him stuff like "its weird that you let your sister feed you lunch" or "siblings shouldn't walk around holding hands, acting all lovey-dovey". I can't have them getting in the way of my relationship with my precious brother by filling his head with this nonsense. Even worse are the sneaky women at his office who try to chat him up when I'm not around! It would be better if he didn't have to go to work and just let me take care of him then nobody will get in my way and I'll have him all to myself, the way it should be! I love him and I'll make him realize he loves me too.