The boy was just four years old when his mother Ellie Price's body was discovered in the bedroom of her South Melbourne home on May 4, 2020.
Police had carried out a welfare check on the 26-year-old, finding Ms Price with plunging stab wounds and a cut to her neck, after she failed to answer calls from family interstate.
Her boyfriend Ricardo Barbaro fled to NSW and was arrested 10 days later. He was found guilty of murder in September 2023.
Ms Price's sister Danielle told Victoria's Supreme Court on Monday she was now raising her nephew, who remains traumatised years after his mother's death.
"It's so hard to explain to him, so I tell him the truth. He wants to know why did he kill her? How did he kill her?" Ms Price said in a victim impact statement.
"(He) asked us if we could go and dig her up, and bring her back because he misses his mum so much.
"His only wish in the world is to have his mum back.
"When we go to Ellie's grave he lays down to be near her. He always says how much he needs his mother."
Ms Price also said her nephew, who is now eight and lives in Tasmania, had been the subject of schoolyard bullying in relation to his mother's death.
"He has been tormented at school by other children saying nasty things like 'you haven't got a mum, your mum's dead. This affects (him) and upsets him so much," she said.
"How do you answer to a child asking why his mother isn't here anymore?"
Ms Price's mother Tracey Gangell told the court her own life was irrevocably damaged since her daughter's murder.
"This is a pain you can't describe, an emptiness you can't fulfil," she told the court.
"My life has fallen apart since you left. What parent needs to be writing this? None in the world.
"I don't even go out and see my friends anymore … they don't ask anymore, because they know I would say no."
Ms Price and her killer dated from October 2019 until the murder when she succumbed to multiple stab wounds including one across her larynx.
After her death, Barbaro left the scene in Ms Price's Mercedes Benz before dumping the vehicle at a Diggers Rest property, northwest of Melbourne.
He fled to NSW after media reports sought his whereabouts.
1800 RESPECT (1800 737 732)
Lifeline 13 11 14
29°C