The coronial inquest findings on the death of 36-year-old Kamilaroi-Dunghutti man Ricky 'Dougie' Hampson Jr will be delivered on Tuesday, three years after he died in agony from perforated stomach ulcers after being discharged from Dubbo Base Hospital.

The inquest earlier this year heard about a number of failures from medical staff and protocols at Dubbo Hospital, where despite being in "ten out of ten" pain, Mr Hampson was discharged with only paracetamol after a doctor mistakenly believed he was suffering from cannabinoid hyperemesis syndrome (CHS), a drug-related syndrome seen in long-term cannabis users.

At the end of the inquest in March, his father Ricky Hampson Snr said his son was a loud, kind, and happy man.

"But as strong and brave as he was and as warm and caring as he was and as loud as he could be, when he needed help no one heard him," Mr Hampson Snr said at the time.

"He was the life of the party; he was the light of every celebration. Now that light is gone, and we are left in the darkness."

The hearing heard emergency doctor Sokol Nushaj said "cognitive bias" led him to misdiagnose Mr Hampson Jr with CHS after a busy night overseeing the emergency department during the Covid-19 pandemic.

Mr Hampson Jr was given medication, including droperidol - an intravenous drug used to reduce vomiting and nausea - along with morphine, but not a CT scan. He was left overnight in the short-stay unit before being discharged the next day.

Practising emergency physician, Associate Professor Anna Holdgate, told the inquiry the misdiagnosis of CHS as "made without any justification," and the administration of droperidol as below the peer professional standard.

She argued a correct diagnosis with a CT scan identifying the ulcers in a timely manner would have likely been "curative".

"If it is recognised early and treated early you would expect him [Mr Hampson Jr] to survive…and live a normal life," Dr Holdgate said at the time.

Deputy State Coroner Erin Kennedy has been asked to consider whether racism and bias played a role in Mr Hampson Jr's treatment at Dubbo hospital.

The court heard evidence how racism operates in the health system and the need for culturally safe care to be provided to Indigenous patients.

In his closing submission, counsel assisting the coroner, Simeon Beckett SC, said the treatment of Mr Hampson Jr was "inadequate and below the peer-professional standard", and argued the diagnosis by Dr Nushaj was influenced by the fact he had seen other Aboriginal patients with CHS.

"The following conduct of Dr Nushaj…constituted, in my submission, that the knowledge, skill, or judgement possessed, or care exercised by him in the practise of his profession, may be significantly below the standard reasonably expected of a practitioner of an equivalent level of training or experience," Mr Beckett told the inquest.

During the hearing, the father of eight's children and family regularly filled the Dubbo courthouse, many wearing shirts emblazoned with his image and the slogan "Justice for Dougie".

"When my youngest was eight, after losing Doug, he asked: 'If I go to hospital, will they save me?' No child deserves to have these feelings," his sister, Anita Chatfield, told the inquest.

"He [Mr Hampson Jnr] was meant to walk into the Dreamtime as an aged and frail man, warm in his bed, surrounded by his loved ones, leaving behind a lifetime of memories and happy times.

"Instead, he was a young man and died alone in unimaginable pain and suffering because of a system that failed him."

The findings will be delivered on Tuesday August 20 at Lidcombe Coroner's Court, NSW.