Backstory: My fiance's family has been a nightmare for both of us throughout the entire wedding planning process. I am in therapy because of it and my fiance has asked his family to refrain from being involved from now own. A integral part of this misery has been his sister, who has been quite rude about things, especially to my fiance.
His sister has three young kids, and they are all invited to the wedding, which is fine. The problem we are having is that we are unsure about giving her a plus one because we are paying for all of her kids and her to attend the wedding already. We are nervous, because the men his sister brings around are without fail quite scary, and I mean scary (like in and out of prison for revenge porn scary).
So, should we give her a plus one? Is it horribly rude not to, given the circumstances? We want our wedding to be pleasant, but we also do not want to be rude, especially because our other siblings (who do not have kids) are getting a plus one, but they also have not been extremely rude and out of line throughout our planning process.