Should I tell my brother his wife isn't allowing me a plus one to his birthday?
Background info: I (26F) have a best friend, we'll call Grace, who is considered family by my parents and siblings. She even lived with us for several years when we were kids because she didn't have a great home life. She has been in every family photo, attended almost every birthday, holiday, vacation, etc. I have two older brothers who are 30 and 39, both are married and neither of my sisters in law seem to like Grace. Both have said she acts inappropriately around my brothers. I strongly disagree, we all act like siblings.
Problem: I was invited to my brother's 40th birthday party hosted by his wife. The guest list is easily visible and everyone gets a plus one. I noticed Grace was not on the guest list so I asked my brother's wife. She gave me some excuse about how he picked the guest list and she was just doing what he wants. I told her that since I have a plus one I'll be bringing Grace. She said that grace was not welcome and if I showed up with her, neither would be allowed in. I asked her why I wasn't allowed a plus one then and she said I was. We went back and forth before she finally said she would talk to my brother and get back to me.
This morning she texted me saying she talked to my brother and explained again that grace is not welcome and if I bring her we won't be allowed in.
I do not believe for a second she actually talked to him and I believe he's going to be pissed when he finds out what she's doing. I tried to talk to my other sister in law and she said I needed to listen to my other SIL and not bring her.
So here's where I need advice. How do I talk to my brother about how his wife is acting? I don't want to jump into accusing her of anything but he needs to know she's being controlling.
UPDATE: I sent a text to my brother to call me when he can. Hopefully I'll have answers later today. Thanks everyone!
UPDATE 2: I talked to my brother and I'm even more confused and upset. He accused Grace of constantly flirting with him and my other brother, being rude to their wives and other shit. I tried to explain to him none of that was actually true and he should know that Grace is just outgoing and quirky. She would never do anything like that intentionally. He told me to drop it and if I show up with her he will go no contact with ME. I have no idea how we got here.
I immediately called Grace and told her what was going on. We had a good laugh at how insane all this is and decided we needed to meet up with my sisters in law to get to the bottom of it. I asked them out to lunch like one commenter suggested but they don't know Grace will be there too. I'll update after lunch tomorrow and once I have all this straightened out.