Prince William Calls Prince Harry and Uncle Charles Spencer ‘Traitors’ Amid New Princess Diana Book

Between Prince Harry and Meghan Markle‘s return to the U.K. and the jaw-dropping claims Princess Diana‘s brother Charles Spencer made about King Charles III in his new book Swan Song: Diana, My Sister, Princess Kate is working overtime to keep Prince William calm, a source tells Star.

“William is a man on the edge right now. You can practically see the stress vibrating off of him. It’s terrible,” says the source. “He’s worried about his father, he’s worried about the future of the monarchy, he’s worried about what his brother is going to do next.”

Kate, on the other hand, “says they can’t get caught up in this ugly mess,” the source shares. “They need to stay focused on protecting the crown and remaining dignified representatives.”

The Princess of Wales, 44, is “trying to do everything she can to help William,” adds the source, from listening to guided meditations to doing breathwork together. “She’s even trying to get him to do yoga, anything to relax a little.”

That may be easier said than done, though.

“William is seeing this alliance that Harry has formed with their uncle and it’s got him incensed and calling both [of them] traitors,” reveals the source. “He’s got no doubts that Harry read his uncle’s book before it was published and he wants to tear into him over it.”

Charles, however, “won’t do anything about it,” the source notes. “He’s too afraid of the Sussexes’ wrath.”

In response to the bombshells Earl Spencer, 62, dropped in his memoir, including that the 77-year-old monarch “sounded giddily elated — like a lottery winner” after Diana’s death in 1997, Buckingham Palace issued a statement, per NBC News.

“While we do not comment on books as a matter of principle, His Majesty is mindful that the pain of fraternal grief can cloud reason, affect judgment and color memory in ways others do not recognize, even many years after such a loss,” it read.