We just got engaged!!! But bro in law is hating 🤬 just venting

So my (now) fiancé and I have been together for almost 3 years now. He just proposed and of course, I said yessss!!! 💍That same day we called our families and everyone was super excited. Only one that didn’t answer was his brother. He finally calls him back 2 days later and starts saying, “why do people get engaged? Is it a commitment thing? The way you proposed was lame, I thought it was going to be over the top. Did you do it because you felt you had to?” And at the end, he texts him “I’m happy with whatever decision you make.” He just made it sound like he doesn’t agree with the engagement.

Now note, he’s been married TWICE. He’s currently married and they have been having so many problems, so much that his wife has told me and my fiancé that she’s going to leave him for good at least 3 times this year. I don’t judge them whatsoever, I never make comments and neither does my fiancé. We’re supportive and All we say is, do what you gotta do. Whatever thoughts we have concerning their marriage, we keep to ourselves because it’s not our business to talk 💩

I don’t care whether people agree or not. And he proposed where he realized he had fallen in love with me 2+ years ago and it was a total surprise to me. So to me, it was special. But he’s upset with the way his brother reacted. And I totally get it and it makes me upset that his brother can’t just be happy for him. I thought he liked me but now idk and now I don’t even wanna hang out with him or his wife because now they’re looking so fake.

My fiancé had his mind set that his brother would be his best man but now I don’t agree. But obviously, I’ll have my fiancé’s back with whoever he chooses.