Sheldon Currie, 18, died in the Princess Alexandra Hospital in February, four days after he was taken there from Brisbane’s Arthur Gorrie Correctional Centre.
Indigenous activists claim jail staff ignored his repeated requests for medical care while he was in jail.
They say he became progressively worse and ended up on life support in hospital but he could not be saved.
His death has been referred to the coroner.
At a protest outside Parliament House in Brisbane on Thursday, Mr Currie’s mother Donna Smith said she was denied access to her son the night before he died.
“I was treated badly at the hospital, very bad,” she said. “I was sleeping on the floor in the hospital, then I was turned away from his bed the night before I lost him.
“I don’t know (why), because he was a prisoner I suppose. But he couldn’t do anything or hurt anyone.”
Calls for full investigation
Ms Smith and her family was due to meet with Corrective Services Minister Neil Roberts on Thursday afternoon.
The minister has already promised a thorough investigation into Mr Currie’s death.
“Any death of a young person, any death in custody is something that needs to be fully investigated and that will happen,” Mr Roberts told the ABC.
Earlier, indigenous activist Sam Watson said Mr Currie did not receive proper medical care in jail despite his repeated requests to see a doctor.
“He was just given Panadol and sent back to his cell,” Mr Watson said. “But he was that ill that prison mates had to hold him up so he could walk.”
Prison chaplain Reverend Alex Gater, who works closely with Aborigines in custody, told the ABC Mr Currie had spent five weeks on remand for minor offences before falling ill.
She said he should never have been placed in prison because he had a pre-existing medical condition.
“He was ill for six days. The first time he had gone to the medical centre he was given Panadol,” she said.
Protest rally in Canberra
“Other times he had gone back he was told there was nothing wrong with him.
“Towards the end, the Murri (Queensland Aboriginal) boys in his unit had to carry him because he could hardly walk.
“…They yelled out to the officer to get him to the hospital because something was wrong but one of the officers said: ‘Well if he can go to the toilet there is nothing wrong with him’.”
Mr Currie’s death comes at a sensitive time for Queensland’s Aboriginal community.
A third inquest is currently under way in north Queensland into the 2004 death in custody of Palm Island man Mulrunji Doomadgee.
Some of the protesters at the Parliament House rally held signs saying “Stop Black Deaths in Custody”.
But Ms Smith said she didn’t want to turn her son’s death into an issue of race.
“No it’s not racist. I just want to know what happened. He was only a boy,” she said.