A long one but I need an impartial view on this please.
The background is that I recently ended a friendship with someone (let's call her friend A) who I've been close with for nearly 25 years. She has a history of being spiteful about people behind their backs, and our friendship took a big hit a few years ago when she shared some very personal information about me to mutual friends. We had a huge row after it but eventually made up, but I haven't trusted her since.
Over the past year or so we have seen a lot more of each other as we now have children the same age (my DS is 1.5 and her child a few months older.) Due to this I have noticed that her meanness has escalated; she doesn't have anything nice to say about anyone including our friends. She has said horrible things about close friends of ours, for example when a close friend of ours, (friend B) got her PHD friend A said behind her back that she didn't deserve it because she has had financial help from her parents. Another friend has had a rough time at work recently and friend A said that she didn't understand why she is even stressed because that friend works in the private sector (friend A has a demanding job in the public sector, but cannot seem to see that other people in different jobs also have a difficult time.) I argued against both comments at the time they were made. There have been countless occasions recently where friend A has shared sensitive information about people we both know or made mean, unsympathetic and judgemental comments about people and it got to a point where I couldn't stand to be around her anymore. I decided to send her a message explaining in a clear way why I don't feel as close to her anymore, trying to be as diplomatic as possible but still calling out her behaviour. I'm sad that I had to do this, but I am totally sure that I made the right decision. She has since deleted me off all social media and left our mutual friend group on WhatsApp, which I guess is understandable as she must be hurt.
Anyway, to the party issue.....Friend B (the one with the PHD, doesnt know about what friend A has said about her, friend A and I have known her for approx 15 years) has a DS who is turning 1 in July, and she wants both friend A and I to be there with our children (I have a DS 1.5 and Friend A has a DD 2 and a DS 4.5.) Friend A is point blank refusing to attend the party if my family go as 'it would be too difficult and upsetting' for her children. I would see her DD (2) say every fortnight for a playdate with my DS and would say that I have seen her DS (4) maybe three times in 2024. I have said that I can stay home and let my DH and DS go to the party without me but friend A is insisting that she still won't go as it will be confusing and upsetting for her kids. AIBU to think that the kids are too young to understand the complexities of the situation, and that friend A is making this all about herself? I feel really sorry for our mutual friend who is in the middle of all this. It just feels like friend A is being really manipulative.