This ain’t no love story. Tatum O’Neal has blamed half-brother Redmond’s shocking descent into a devil-horned suspected stabber on years of “horrifying and cruel” abuse by their late dad, Hollywood legend Ryan O’Neill. The former child star gave her damning indictment after Redmond made a terrifying vision with horns tattooed on his head as he appeared in a California court charged with attempted murder. “He’s doing very poorly, honey, very poorly,” Tatum, 62, told the Daily Mail of her troubled half-brother, the only child of Ryan O’Neal and Farrah Fawcett . Remond O’Neal appeared in court with devil horns tattooed on his head last month. Frederick M. Brown for CA Post “I love Red dearly, but he’s gotten heavy. He never even began a real life,” she said. Tatum blamed Redmond’s issues on their notoriously dysfunctional childhood, saying that her half-brother has “never changed.” “It was always drugs, drugs, drugs,” said the actress, who has had her own headline-grabbing issues with addiction.…