Kevin Federline has claimed his sons are worried about their famous mum, Britney Spears, and have stopped seeing her again. Federline revealed the news to Piers Morgan during Thursday's episode of his YouTube talk show, Piers Morgan Uncensored. "She saw one of my sons one day this year, and he decided not to go back over there because of what he saw," said Federline of the former couple's son, Sean, 20. "The other one, Jayden, who's my younger son, is 19 now. He's been over there quite a few times over the past year, and he's stopped seeing her in the last few months because of the situation," he shared. Federline claimed that their sons are "terrified" and "worried about their mom", and said they "don't know how to help because of what all of this has cost". When asked why Spears' sons don't want to be around her, and what they may have seen, Federline said, "That's not my story to tell." "That's my sons' story to tell if they decide to. I mean, the things that they've seen are shocking, right?" the former backup dancer alleged. "So shocking that one of my sons came to me and called me and was like, 'I don't know what to do. I'm afraid Mom is going to die.'" Federline dropped his memoir, You Thought You Knew, earlier this week.