Kim Male looked directly at Mason Matticoli, 25, and Tyler Van De Steeg, 30, as they pleaded guilty to the manslaughter of her son Jackson Gilmour, 29.
Van De Steeg wiped away tears while Matticoli looked straight ahead as Ms Male offered them compassion in the Victorian Supreme Court.
"Hope is the only reason I can stand here today," the mother said on Monday.
"It is the reason I can say to the young men responsible for taking Jack's life that I truly hope that they can use this time in front of them ... to help other young men to make better choices."
Mr Gilmour was killed in the early hours of December 2, 2024, when Matticoli, Van De Steeg and Charli Hayter broke into his home at Rye, southeast of Melbourne.
Ms Hayter had earlier contacted Mr Gilmour to seek drugs, but he and his partner were asleep when the trio smashed a window and barged into his house about 4am.
Mr Gilmour jumped out of bed and there was shouting before he was shot dead by either Van De Steeg or Matticoli.
Ms Hayter also suffered a fatal gunshot wound, although no one has been charged over her death.
Van De Steeg and Matticoli fled the scene in a stolen car, which was later set on fire by Jarod Smit, 26.
Smit on Monday pleaded guilty to a single charge of arson, while Van De Steeg and Matticoli pleaded guilty to manslaughter after originally being charged with murder.
Mr Gilmour's loved ones packed the court for the plea hearing, during which four victim impact statements were read aloud.
Sam Male told the court while Mr Gilmour was far from perfect, he was still the best big brother.
"He fought so hard to become the man that we all knew and loved," he told the court.
"My heart will forever be broken."
Lawyers for Van De Steeg and Matticoli both described how their clients had descended into the use of illicit substances around the time of the manslaughter.
Barrister John Desmond, representing Matticoli, said his client had been abusing methamphetamine, cocaine and prescription medication.
Matticoli had no criminal history and his rehabilitation prospects should be considered promising given he was still a young man, Mr Desmond said.
Van De Steeg had also abused drugs, but he was now abstinent and finally medicated for his complex mental health concerns, barrister Emily Clark said.
He was remorseful for his crime, she added, pointing to comments to a psychologist in which he wished he could go back and change everything.
The two killers were facing lengthy jail terms, but Smit's barrister Alexander Patton argued his client should not be sent back to prison.
He had already spent nine months in custody before he was bailed so the judge could take that time into account in sentencing, Mr Patton said.
Outside court, Kim Male told reporters she forgave her son's killers.
"I don't think anyone starts a day intending to ruin it, to ruin their lives like they have," she said.
"I do forgive them - absolutely. I'm devastated, my son's not here, but I don't have room for anger."
Justice Amanda Fox will sentence the three men in July.