If I was in a my brother's wedding, do I need to include him and my sister-in-law in my wedding party? My brother and I don't always get along. I think my SIL would really like to be the wedding, and my mother is telling me they both need to be in the wedding. If i include my SIL, do I have to have my brother. Or should i just leave them both out. Also, my FI isn't all that thrilled about my brother being a groomsman.