The mother of a 26-year-old man slain by his best friend in a Sydney park has told a court she forgives his killer, who was on a drug bender.

Liam Anderson – the son of Rose Tattoo rocker Angry Anderson – died in November 2018 after Mathew Flame stomped on his head repeatedly because he thought his friend had turned into a demon.

During the trial, jurors heard Flame, 22, took up to 10 MDMA pills at a Darlinghurst party before ending up at a park with Liam on the northern beaches.

In November, he was found guilty of manslaughter in the NSW Supreme Court.

On Tuesday, Liam’s mother Lindy Anderson fought back tears as she told the court she had forgiven Flame.

“Forgiveness for me is to find peace in life. I choose to forgive because the poison of anger will only eat me away,” she said.

“If I forgive, my mind becomes calm … I will not let you, Mathew, or anyone else destroy my inner peace.”

Mathew Flame was found guilty of the manslaughter of Liam Anderson.

Ms Anderson said her life had “no purpose” in the months after her son’s death.

“I can’t stop thinking about how scared and frightened Liam must have been and the pain he suffered as his head was continually stomped on,” she said.

“That thought haunts me.

“All I understand, Mathew, is that when Liam died he was trying to protect you.”

Flame, who had spent much of the hearing with his head bowed and eyes closed, looked up as Ms Anderson spoke via video link.

During the trial, a statement from a witness who said Flame showed “no emotion” as he “stomped” on Liam’s head in Pavilion Reserve at Queenscliff was read to the court.

American tourist Trevor Buchert was holidaying in Australia when he saw the attack and told police: “I could see the victim turn his bloodied head towards me and he called out, ‘Help me, help me, help me,’ in a desperate manner as loud as he could.”

Liam Anderson’s mother Lindy leaves court after the verdict in November. Photo: AAP

In his victim impact statement on Tuesday, Angry Anderson, 73, said he had been “condemned to a life of sadness” after his son’s death.

“No day of celebration will ever be the same for us now, because Liam is not there to celebrate or be celebrated,” he said.

“I am condemned as we all are to a life of sadness.

“I now fully understand the meaning of the phrase having a hole in my heart.

“When he died part of me died with him.”

Angry Anderson said another son had phoned him to inform him of Liam’s death.

“I can never forget the sound of his voice,” he said.

“Nothing could have prepared me for the haunted look in my children’s eyes, the pain, the hopelessness, the anger and the overwhelming grief.

“We would be bound together forever in our grief.”

-ABC