Family, friends and those passionate about the cause marched outside Dubbo Hospital on Monday, calling for a coronial inquest into Ricky Hampson Junior's death.
In August 2021, the 36-year-old known as Dougie attended Dubbo Hospital with severe stomach pain and a popping or tearing feeling in his stomach.
His family said he was treated and sedated, given painkillers and sent home without a proper diagnosis, before he died a short time later.
Now they're calling for answers.
His family want a coronial inquest to know why Dougie died.
"Our son can't talk for himself so we've got to give him a voice," his father Ricky Hampson Senior said following the march.
"It's something that he would want to do and we're doing it. He deserves justice. He deserves to have people answer why they didn't treat him well when he was polite to them, he trusted them. They let him down."
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Mr Hampson and his family believe a "simple scan" of Dougie's stomach to see the perforated ulcers could have saved his life.
A spokesperson for the Western NSW Local Health District did not answer when asked by the Daily Liberal if Dougie's death was due to failures within the system.
"We offer our sincere condolences to the family of this man," the spokesperson said.
"The death of this man has been referred to the coroner and the Western NSW Local Health District will assist in the coronial process."
National Justice Project chief executive officer George Newhouse, who is acting for Dougie's parents, said an inquest into his death would provide accountability and changes in the way Aboriginal people were treated in the NSW health system.
"A coronial inquest would provide an opportunity to observe systemic patterns and to prevent deaths in similar circumstances and most importantly to provide transparency and accountability to a system that too often fails Aboriginal people," Mr Newhouse said.
Mr Hampson was emotional as he described his son, a father of eight, as a very caring man.
"There was even a report from the hospital staff that noted down that he was polite to the staff. He was in no way rowdy or anything like that. He was very humble. He was an old soul and he just didn't deserve to die at 36," Mr Hampson said.
"It's devastating. It's absolutely heartbreaking. It's like a nightmare we just can't wake up from it. We live in Yass, which is four hours away and we expect the phone to ring but it just doesn't happen. We haven't really grieved because it's just so unbelievable. He was so young and he had no underlying health conditions."
As well as getting answers on Dougie's death, the family want to see changes within the health system to prevent something similar happening again.
"No more bias, start treating people for the pains and things they're going in with. Look at the red flags, don't assume they've got a condition when they haven't," Mr Hampson said.
"Just start being more aware of what they're being told."
Mr Hampson said he felt his son was with them during the protest.
"People say time heals all wounds but I don't think a parent can ever get over losing a child. No matter their age. We're just devastated," he said.
"I don't even know how we're here...I just think his spirit is here with us today, giving us the strength to keep hold of it."