Gibb died of liver and colon cancer in May aged 62.
His wife, Dwina, told the Daily Mail in Britain he went against doctors' advice to have his cancerous cells properly checked in late 2010, instead choosing to tour Australia and New Zealand, including a charity performance after the Christchurch earthquakes.
Cancerous cells were spotted after surgery for an intestinal blockage in October 2010.
"He didn't want to stop and I said, 'Please just have the scan'. Despite all his wonderful ways, Robin could be very stubborn and he never liked bad news - he just didn't want to know.
"He went to do a show in New Zealand as they'd just experienced an earthquake. Maybe it was very important for him to do that show, but it was still important for him to have his scans."
By the time Gibb had a check-up, the tumour had started to spread to nearby blood vessels.
