Robin Gibb is "fighting" his health problems, according to his son, who said the singer was heartbroken to miss the premiere of their debut classical work.
RJ Gibb, who worked on The Titanic Requiem with his father, said his family were hoping for "a speedy recovery" for the 62-year-old who has been treated for colon cancer and pneumonia.
He told BBC Breakfast: "He is still in hospital, he's fighting infection and of course - as a lot of people who have family members or friends who endure cancer, they know - there are a lot of periphery problems afterwards they have to deal with."
Ongoing health problems forced Robin to miss the premiere of the Titanic work - to mark the centenary of the ship's ill-fated voyage - at London's Westminster City Hall.
RJ Gibb said: "The one place he really wanted to be in two and and a half years and he couldn't be, and it was heartbreaking, but he'll be able to see it. It was recorded and live streamed."
Robin recently underwent surgery for an ongoing problem with a twisted bowel. The same hereditary intestinal condition led to the death of his twin brother Maurice at the age of 53.