King Charles and Kate Middleton are battling cancer at the same time, and experts believe the royal health woes are causing the Princess of Wales and Prince William to think about their future in the royal family. “They’ve had to deal with an enormous amount,” Tina Brown said on CBS Mornings. “Because what people haven’t really thought about is the news Charles, the king, has cancer, which came right as her own operation happened, that brings them much closer to the throne.” “Whatever the prognosis is for Charles, he’s 75 and he has cancer,” Brown continued. “That brings William and Kate far c…