I, 20 year old male, and my brother, 29 year old male, who, for the sake of privacy we'll call Zack, have had a rocky relationship. He would always belittle and bully me when I was younger and still does. Our mother, who we'll call Xara, had fallen in the front yard of mine and her house since I'm the last one still living at home. When the ambulance arrived for my mother, Zack's girlfriend, let's call her Lili, asked the paramedics if I could go with my mom. They said no so I started to walk back inside. Both Zack and Lili tried following me while Zack was yelling at me that he'd take me. I ignored him, handed him my mom's phone and wallet and went inside. Zack then proceeded to say, "Fine. Take your fat ass inside since you won't listen". I then whipped around and yelled back at him, "fuck you too bitch" and slammed the door, locking it so he couldn't come in and try to hurt me because he has serious anger issues. I haven't apologized and Zack still holds it against me. My mom, Xara laughed it off and said, "about time" when I told her what happened. I'm not the type to lash out usually but I had just had enough of his rudeness towards me. AITA?