Over the weekend my parents met my FIs family (mom and his 3 sisters ... His brother has been over the house a lot). During the BBQ my mom was discussing the wedding with him mom and showing her the venue that FI and I have picked out. Fi's oldest sister then goes on a rant about how she can cater our wedding for half and that he's wasting his money (my parents have offered to pay for the reception) by doing what I want. He then told her to knock it off. A couple of hours later as they were getting ready to leave she corners me and tells me that she better be included in my bridal party. I haven't asked anyone yet but I do have people I want to ask and she is not one of them just because she can be so caustic. I do plan on asking his youngest sister because her and I are actually friends.
Does anyone have any advice on how to handle this? Thank you