The right thing for him to do, if he didn’t want to come in your business, would have been to stay quiet all together and not take anyone’s side. In a perfect scenario he would have talked to his wife afterwards - based on your side of the story here - and cleared the air, which he clearly didn’t do. Plus that’s probably what has gotten to her head. So while your brother probably is a good guy, he’s not a very good or balanced husband and brother.
I don’t know why desi people feel being given a free card to talk crap to anyone is the first sign of a good spouse, it isn’t. A good spouse is suppose to make you a better person, not a BS head.