Wow. Leave it to an A to somehow justify making this all about him. He acted like an @ss and now he's mad that someone knows about it. Personal responsibility? Nope. He's deflecting that negative attention on to you. Nice. Guess what? You don't need to accept responsibility for his failings. Neither does your sister. This is his to own. So, you can just let it be his.
I'm sorry that your sister's actions ended up making your day more unpleasant. Her intentions were no doubt very good, and her actions may have worked on any non self-absorbed person. But, she obviously hasn't learned how and why you would disengage from arguments with an alcoholic. Maybe you and your sister can go to an AlAnon meeting together? You need to gather your support around you right now.
We are here for you too.
Many hugs,
Fathom