IIRC, Brian Keith killed himself rather than suffer with the disease.
During the later part of his life, Keith suffered from emphysema and lung cancer despite having quit smoking ten years earlier (he appeared in an endorsement campaign for Camel cigarettes in 1955). He was found dead of a self-inflicted gunshot wound[3] in Malibu, California on June 24, 1997, two months after his daughter Daisy committed suicide. It was also reported that he had financial problems and suffered from depression throughout his final days. Keith’s family were joined by many mourners at a private funeral, including Family Affair co-stars Johnny Whitaker and Kathy Garver, and Hardcastle & McCormick co-star Daniel Hugh Kelly.
His remains are buried next to those of his daughter Daisy at Westwood Village Memorial Park Cemetery in Los Angeles, California.
Uncle Bill offed himself? What about Mr. French?