The first man to be convicted under one-punch laws in NSW has fallen asleep in court as his victim’s mother detailed her pain at losing her only son.

ABC reported that Hugh Bacalla Garth, who faces at least eight years behind bars, fell asleep “several times” as he watched proceedings in the NSW District Court via a video link.

Garth, 25, was convicted in May of unlawful assault causing death after punching Raynor Manalad outside a friend’s 21st birthday party at Rooty Hill in Sydney’s west in May 2014.

Mr Manalad died in Westmead Hospital the next day after sustaining extensive bleeding on the brain.

During his trial in May 2017, Garth admitted that he had drunk a lot of alcohol on the night Mr Manalad died, but said he had acted in self-defence during the fight outside the party.

He became the first man to be convicted under NSW’s one-punch laws that apply to anyone found guilty of a single punch attack while under the influence of alcohol or drugs.

Garth faces a mandatory minimum eight-year jail sentence, but could be sentenced for up to 25 years.

Mr Manalad’s mother, Teresita, told the court of her anguish not only at her only son’s death, but at her frustration that the case had dragged on for almost 3½ years.

“Enough,” Mrs Manalad told the court on Friday.

“I’m sick and tired of this. I’m tired – let’s end this. There are a lot of things I can concentrate on [instead].”

Mrs Manalad said she and her husband “have accepted we are going to go through this until the day we die”.

“As nurses we are very tolerant people … why do I have to prove how I feel?” she said reading from a victim impact statement.

“I’ve lost my son. That is what it is all about from day one.”

But the mother’s heart-wrenching speech appeared to have no impact on Garth who reportedly “drifted off several times during the hearing”.

Ms Manalad told the court how her son, a qualified nurse, was both the life of the party and always looking out for others.

He would have turned 25 next month and had planned to become a psychiatrist to help those with addictions to alcohol and other drugs.

“Isn’t it ironic about how he died and how he was killed,” Ms Manalad noted.

Judge Antony Townsden thanked her for her bravery in addressing the court.

“I have to be brave for Ray and this is the justice I can give him,” she said.

“The strong mother, the rock.”

Garth’s sentence is unlikely to be known before December as his defence team has questioned the constitutional validity of the mandatory minimum term.

The case is expected to return to the District Court in October.

– with ABC/AAP