My mum has always been difficult. My memories of my childhood are pretty awful. She's now in her early 70s; covid seems to have hit her very hard and left her very depressed. She does have positive qualities, and I can see that she is miserable and lonely. But I know that, invariably, she will make any significant life event extra stressful, either by having tantrums or making unpleasant comments if it's something positive, or kicking off about how I've ruined my life/how much worse things are for her if it's negative. That is just how she is. She would be mortified to hear it, but it's the case.
I have two brothers both of whom have wives and children; we're all in our late 30s/early 40s. For a while we tried doing family Christmas with mum hosting, which she desperately wanted to do, although in practice it meant me cooking in a filthy kitchen while she had a tantrum/panic and got very stressed. Over the years, one or other of us would say we were doing Christmas with our partners, and she would organise an 'alternative Christmas' where the same thing would happen. She is absolutely fanatical about this. She is also furiously jealous of her children's in-laws and will rant for ages about how unfair any arrangement is. For a while my younger brother and his wife did alternate Christmases with each set of in-laws, as they live nearby. My mum constantly complained about being invited to a Christmas that was not perfectly to her taste, whinged loudly about every detail, and generally made herself objectionable.
Gradually, both of my brothers have reduced levels of contact, which I find understandable.
My dad reinforces all of this. I don't get the sense he is miserable and lonely - he's still working which keeps him busy - but he actively encourages mum to see everyone as against her. An example would be: mum's a keen gardener with a lovely garden, but had some health issues and needed help. I found her a gardener happy to do a trial run. Instantly mum picked holes in every trivial thing this woman did - she'd trimmed grass an inch too far; she'd used shears for this when mum would use scissors. I couldn't get her to see that these things were trivial, or to accept that it would be ok just to say 'actually, this isn't working but thanks'. A few weeks in the gardener got in touch and said tactfully that she didn't feel it was working out. Weeks later, mum is still bitching about her, going on about how little she seemed to know and how poor her work was, while my dad smugly reinforces it by telling us all how talented mum is. My dad informed us that we should think of it as if mum was a master painter making great art, and she shouldn't have to put up with being assisted by someone who spoilt a masterpiece.
Everything in her life is like this: she is sure she is right and she has levels of knowledge/talent far beyond anyone around her, and my dad will always agree with her. So, for example, she volunteers at the local school to listen to children reading, and she becomes furious and frustrated that the qualified teachers and the headteacher do not take her perspective more seriously. She has some background in education (she did volunteer work for years), and when she was younger my brother and I tried hard to encourage her with that because she wanted to make a career out of it. But she wants to go in at a very high level and be treated as an expert, and it just wasn't going to happen without her putting in the work and the time to get qualifications or develop a career.
I don't want to have a massive showdown or 'go no contact'. But I've also hit the point where I just can't take it any more. For years I've done grey rock religiously and I've got very good at nodding and changing the subject. But increasingly, I feel very uncomfortable at the level of vitriol at other people she expects me to absorb. This Christmas she was ill and I saw both of my brothers (separately) with their families, and it was just lovely for me and for my DD. I really don't think I am being unreasonable here (I mean, say if I am). But I would like to know how other people in similar situations have managed it.