It's never really about the politics! Your sister was just using that as a stick to beat you! One of my brothers has done the same to me since 23 June 2016. Unfortunately, it coincided with me staying with him to attend a (non-political) conference nearby. He has always complained that nobody ever come to stay with him, so I stayed one more time and was shouted at and berated over Brexit yet again. It was useless trying to have a discussion about it, and I realised that I needed to drop any idealised idea of filial closeness. I resolved never to stay with him again. Since then I've stayed nearby with my nephew and also in a Premier Inn. He has stayed with me lots of times in the past, and can do so again, if he wishes, but I will not permit him to verbally abuse me. It arises from difficulties he had in childhood with what would now be called ADHD and dyslexia, which was unrecognised at the time by parents and school. I am the eldest, and I was put in charge of him going to school and at school. He was badly bullied and I had to protect him from the bullies, or get into trouble from our parents. Despite having had a very successful career in a technical field, having built his own house in a 'posh' area, and having all the accoutrements of a successful life, and lovely children who have done very well, he carries huge resentment. Although I have never spoken of those miserable days (it made me miserable too!) I think he associates me with those times and so he takes it out on me. I have realised that I will never change him - his impulsiveness shows in his emotional incontinence. I handle the situation by keeping meetings short and 'jolly'. It's a shame, but you can't choose your relatives! Fortunately, I am very close to my youngest brother, who was too young to realise what was going on in our childhood. I would say you should go to the meeting, paint the smile on your face, keep it light, and remove yourself if she starts to abuse you. Good luck!