When Indigenous man Dougie presented to Dubbo Hospital in NSW he told the nurse he heard a "popping sound" tearing inside his stomach.
Ricky Hampson (Dougie) Jnr was then sedated, given painkillers and discharged just 19 hours later with no diagnosis, his family has confirmed.
The 36-year-old Kamilaroi-Dunghutti man died from perforated duodenal ulcers in the early hours of the following morning on August 16, 2021.
The father of eight children leaves behind a devastated family, including his father Rick who blames the hospital staff's discriminatory treatment.
"I do feel he was mistreated, there was an internal investigation in the hospital after and they admitted to treating him with bias," Mr Hampson told AAP.
"It's still so hard to believe, we're numb inside. It's like we're waiting to wake up and find out it's not real. So incomprehensible, it's unbelievable.
"A normal person like me with no medical background figures if something has popped inside you, and you're feeling ten out of ten pain, we should do some imaging or something.
"But they just doped him up, put him aside to sleep and let him go 19 hours later.
"In the medical profession where life matters, you can't be racist, you go into this profession to care for people, everyone should be treated the same."
Mr Hampson said his son recorded a COVID-19 positive test on August 15 after he was discharged, but "nobody bothered to ever tell him".
Dougie's mother Lydia Chatfield and father are hoping for a public coronial inquest into his death and wants to see those who let their son down accountable.
National Justice Project chief executive George Newhouse said he receives "a lot of complaints" from Indigenous Australians about the standard of care they receive at Dubbo Hospital.
"I've been told they are prepared to drive four hours to Sydney to get medical treatment rather than attend Dubbo Hospital," he told AAP.
"If Dougie was kept longer under observation there's no doubt in my mind that they would have discovered his serious illness and he would be alive today."
Mr Newhouse acknowledged the significant pressure hospitals face.
But following coronial inquests such as that of Naomi Williams, which found implicit bias in her mistreatment, Mr Newhouse is concerned those lessons are not being enforced in NSW health services.
"It is absolutely essential that hospitals provide culturally safe care to First Nations people," he said.
"I see a number of cases all around Australia where Aboriginal people are discharged without a proper diagnosis and they go home to die."
A Western NSW Local Health district spokesman in a statement offered their sincere condolences to Dougie's family.
"The death of this man has been referred to the Coroner and the Western NSW Local Health will assist in the Coronial process."
Due to the ongoing investigation no further comment was given.
Dougie's family will be holding a protest in Teresa Maliphant Park opposite Dubbo Hospital on Monday.