help! i need to stop my brother from making a terrible mistake

*LONG STORY!!*

so a little back story

my brother and his now fiance have been together since high school. she was my brother's first and only gf. they have been together about 6 years. this past Christmas, he proposed, and now her true colours are coming out like crazy!

she's always been pretty controlling with him (he's not allowed to drink, or really have any guys nights. now that I think about it, he's basically lost any guy friends he had because he's never allowed to hang out with them). But now with the wedding coming up in less than a year, she's let her crazy out big time! She had my brother come over and ask me if I really wanted my 2 children to come to the wedding . I said well, they are your nephews (and really the only young children in our family) so ya, I'd probably want to bring them for a little bit (not the whole night) as they are family. my brother has always been super involved with my kids, he loves kids, but she HATES kids. and openly admits it. He told me ok, we just don't want anything getting broken and kids running around at our wedding, to which I responded since when have I ever been the type of mom to let my kids run rampant around anywhere? so that was settled, or so I thought. My mother calls me and tells me that they told her the wedding will now be 12+, no kids. my kids are the only ones under that age 😒

however she still wants them to come hours before the wedding so they can be in pictures, she just "really doesnt like kids" (those were her own damn words) so she doesn't want them there for "her day". I don't know how to feel about this. my mom then tells me that even though she offered to pay for an open bar at their wedding, the bride has said no, her family doesn't drink and they think our family will "take advantage" and embarrass her and her family. let me just say, my family members are by no means drunks or people that would ever make a scene or anything like that. it's just something that is a etiquette thing in my family that you have an open bar for people instead of making them pay, especially since you have a certain level of expectation for people to give cash as gifts to you. no, the bride wants a cash bar so that people don't get drunk. whatever girl.

she got engagement photos done recently (which my brother paid for), and I kid you not, every single picture is of her!!!!!! my brothers face is not in a single one! he literally could have been some random stand in model, you'd never know! it's all about her.

my brother is sooooo good with kids, he would make the best dad. their whole relationship they have talked about kids, but now that she has a ring on her finger, she's decided she doesn't want kids after all. she says they will just have dogs. my brother is expected to just go along with this.

these are just a few instances of red flags for my family about this woman out of many. my brother is so blinded , and honestly I think he thinks he won't find anyone else, and he's super passive, so he never sticks up for himself. I need help deciding if I should try to say something to him, to see if this is really what he wants. my mom has tried, and he just ends up sticking up for her and not listening to a word. my mom wants me to try before he's actually married to this person who so obviously isn't right for him. I don't want my brother to hate me, but I also don't want to stand back and watch him make a huge mistake. any input is appreciated.