When the consultant surgeon reviewed him on the third day, he didn't identify any deterioration and so the plan for conservative treatment was maintained.
On the fourth day, the man's condition worsened and he underwent urgent surgery, which showed extensive faecal contamination from a hole in his bowel.
He died soon after surgery from septicaemia.
His daughter - who is a health professional- complained to Government-funded health watchdog the Health and Disability Commission (HDC) because she believed there was a missed opportunity to save her dad.
She told HDC that she'd asked the nursing staff on several occasions whether her father was septic as she was concerned about him hallucinating, becoming delirious and being short of breath.
"We were told he didn't have sepsis," she said to HDC.
"We were told that [his] recovery would be a long process, but all indications given at that time, were that he would survive," she told HDC.
On that advice, she and her family returned home. They never got to say their final goodbye as he died that evening.
Today, HDC released a decision finding the surgeon in breach of the agency's code of consumer rights for not recognising a patient's deteriorating condition and providing the appropriate intervention.
Health and Disability commissioner Morag McDowell said she acknowledged that the signs of sepsis were subtle and non-typical, however, it was well documented in the clinical notes that in his final 24 hours, the man had multiple reviews indicating that he was not well.
"Based on this, and the expert evidence, a deterioration in the man's condition is evident," McDowell said.
The commissioner ordered the surgeon to issue a written apology to the family and recommended further training for decision-making and sepsis.
