Why don't Paul and Ruth talk anymore?
I think there’s a couple of reasons, and I should clarify before I start that Ruth is only Paul’s step-sister (important because had she been blood, I think Paul’s attitude would be much different).
1. Given that their only connection is Jim, who died in 1976, then it’s perhaps understandable that they would have lost touch. Paul would only have seen Ruth once or twice a year between 1964 - 1976, and not only was he 18 years older than her, but he had his own hectic life. It’s fairly common for step-siblings to drift apart in situations such as this.
2. After Jim’s death Angie auctioned off some of Paul’s childhood mementos, including his birth certificate and a pair of baby shoes. Ruth defends her mother’s decision saying that while Jim was alive, Paul gave them £7,000 a year, but once he died, they received no financial support at all. Nevertheless this could be seen as a betrayal by Paul, who has had his private life and belongings sold to the press and public by “friends” and “family” since about 1963.
3. Although Ruth was quite quiet about Paul for some time, in 1994 she gave an interview to Geoffrey Guiliano (oof), which painted Paul in a very negative light. Guiliano later gave the tapes to Heather Mills' legal team during her divorce from Paul, to substantiate her claims of abuse, because among stories told in the tapes was one from when Ruth was 15:
She’d just done a TV show as a backing dancer, and told Paul she wanted to do it as a career, but according to her, Paul launched a tirade against her telling her that she was a “spotty teenager”, “worthless”, and that “boys were only interested in [her] to get to him.” But even at the time of the interview she was very forgiving of Paul, saying that now she’s older and wiser, she understands that this was his version of tough love, that he’d had his life ripped about by fame and couldn’t see it happen to her.
4. In the same interviews she told a story of Linda McCartney reading Angie’s diary, and Ruth called her a “a nosy cow”. A small blip on the radar maybe, but it could be yet another warning light for Paul. She has also recently come out and said that she regrets giving the interviews, especially seeing how they were used against him in court. She says about their estrangement that there was never, “any major row," Paul just stopped talking to her, but that she still loves him, and has a lot of fond memories of him as a big brother.