Keep your neutral stance. They will hopefully sort it out in the end, but if not, it's their misfortune. With me it's estrangement with my DDs and I break my heart every day, but when I attended my mum's funeral (they were not going to let me know, but the solicitor advised me and I went with MIL, one of her best friends), I said to them "Let's build bridges and try to make peace". They snubbed me, at which point I decided life's too short to worry about petty-minded people, even my much-loved daughters. My DS long ago decided that, although he has always wanted to be reconciled, they won't listen, so has decided that to him they are dead.