I have known of two men upon remarriage after the death of a partner, who left everything to the new partner, despite always previously had a good relationship with their children. I got nothing off my own father for that reason, but I had no animosity as we had always been close and the new wife was in control from day one. I and my siblings never challenged it.
Fast forward twenty years, my only daughter whom I always adored estranged me. Nothing I did would bring her to discuss it with me. A few years later I went to a solicitor to change my will but cancelled it as I was in floods of tears, the lady solicitor was so upset and she said leave it a while it's too raw, I left it two years and went back to her and finally did it. After, she told me it was far from uncommon, that more arguments came after will reading than you would think. She then added, I can't think how you must feel but know you're not alone.
I've never forgotten her kindness.
It's a huge step for any parent to take, we shouldn't be judged, I didn't judge my father, he was a good man who unfortunately made a bad choice of wife, he had said that to me but couldnt face a divorce as he wasn't in the best of health, he married too soon after my mother died.
At the end if the day it's just money, no one might get anything if we live long enough to use it all up on care. If there is any spare cash help them now whilst you can is my thoughts on it but it's up to the individual.
Some estranged parents are bad but so are some estranged children.