The body of 73-year-old William Trotter - or Bill to those who knew him - has remained in cold storage at a Newcastle mortuary for the last 14 months as his son Mike Trotter, 47, and daughter Kelly, 42, have battled to establish why he died.
Hospital bosses say there were no failings in his care.
But Mike and Kelly are challenging this and want to overturn a coroner's decision to not hold an inquest based on a ruling that Mr Trotter's died from "natural causes."
The family refute this, saying that when Mr Trotter was admitted to hospital on May 8 last year, he was did not have the perianal abscess that led to the sepsis blood infection that killed him.
They insist he acquired the abscess in hospital.
So that means, said Kelly and Mike, that their father's death should not have been classified as being from a "natural" cause and it should therefore be investigated at an inquest, a request rejected by the area's senior coroner.
The brother and sister believe they have uncovered a catalogue of mistakes in the care given to their father in the weeks before he died on July 18 last year, including:
All four doctors directly involved with his father's care have now left the North Cumbria Integrated Care NHS Trust, which runs the hospital.
In a statement, the Trotter family said they believe they are now witnessing "regulatory failure" at multiple levels as they work their way through several public bodies in the hope of holding the trust to account.
"We've fought for over a year to get answers," said the statement. "This looks like a system designed to protect professionals and institutions, not patients."
Kelly added: "The last year has been extremely hard.
"Our father was a strong and active man, whose priority was always his grandchildren. He also loved going for meals and coffees with our mum.
"We know that he did not have a perianal abscess when he went into the hospital; the trust has confirmed this in a letter. So our obviously got the abscess in hospital.
"So how can they classify his death as natural? A perianal abscess can be seen as a natural cause of death.
"According to the National Institute for Health, an abscess acquired in a hospital should not classified as a natural cause of death; and our dad did not have an abscess when he was admitted to the hospital." This was a reference to the professional opinion of the trust's Medical Examiner (ME).
(Image: Contributed)
Mike said: "Our dad was a family man first and foremost. He always put his family first before himself.
"He was also a generous individual, who lived for spending time with his grandkids. He was our world. When he was in that hospital, he was desperate to get out.
"The quality of care was poor - just not what you'd expect from the NHS. But we have been met with continual denials. We'll keep going with this because we don't want it to happen to anybody else."
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As well as building their own website to highlight the issue, the Trotter family have raised their concerns with the General Medical Council, the Care Quality Commission (CQC), NHS England and the Parliamentary and Heath Service Ombudsman.
North Cumbria Integrated Care NHS Foundation Trust issued this response: "We would like to reiterate our deepest sympathies to the family of Mr Trotter at what is a very upsetting and traumatic time.
"The Trust's complaints process aims to be an open and honest review of concerns raised by patients and families. The Trust has conducted a detailed complaint investigation into the multiple issues raised.
"We have responded to these issues in full and shared the outcome with the family.
"A number of meetings were held between the family and senior medical and nursing staff whilst Mr Trotter was an inpatient and during the complaints process.
"Our investigation has not identified any failings in the care provided to Mr Trotter.
"We are sorry we have not been able to resolve the concerns of the family, and they have been advised as to further steps they can consider taking in the event that they do not accept the outcome of the Trust's complaint investigation."
A CQC spokeswoman also offered condolences.
She added: "As soon as we were made aware of the concerns around Mr Trotter's death, we asked the trust to provide evidence around the care and treatment he'd received. The trust provided this information, and it confirmed that no further action was required by CQC.
"We'll continue to monitor the trust in line with our usual processes, to ensure people are receiving safe care and treatment.
"CQC's priority, at all times, is the health and wellbeing of people using health and social care services, and all information we receive informs our monitoring of services and future inspections.
"We would encourage anyone who has concerns about a health and social care service to let us know. This can be done via our customer service centre on 03000 616161 or [email protected]."