ESH. Maybe your brother is a homophobic jerk, or maybe he just doesn't want extended-family drama on his wedding day. Maybe you're bending over backwards and digging in because you want to prove you're different than your family.

You already know your own family and the bride's family are both traditional Evangelicals and I doubt this is the first time you have had inklings about their stance on gay people or gender roles. So your kid attending the wedding in makeup look wasn't going to fly and you knew it.

Don't attend and die on this hill if you like. Be aware it will be a nail in the coffin of whatever relationship you have with your brother---and you're the one who wrote "my kids see him a lot and love him."