Instead of fleeing the home they broke into, two boys slashed at a Wallabies star before cutting his wife to the bone with a sickle.
The teenagers, then 15, were carrying knives - including the cane-cutting implement - when they broke into former Australian rugby player Toutai Kefu's home in the inner-Brisbane suburb of Coorparoo in the early hours of August 16, 2021.
During a confrontation that followed, one teen struck his wife Rachel while Mr Kefu - who used a stool as a barrier to challenge the two intruders - received a 25mm stab wound into his liver.
"The sickle cut Mrs Kefu literally to the bone, so quite apart from the fact it looks like a pretty wicked weapon, it did that," Justice Peter Davis said on Tuesday.
Mr Kefu's son Joshua was cut as he tried to intervene and daughter Madison was also injured.
The boys, who cannot be named for legal reasons, have pleaded guilty in the Supreme Court in Brisbane to charges including intentionally causing grievous bodily harm relating to the home invasion and the theft of a car from another property the same morning.
Crown prosecutor David Finch argued a sentence of not less than 10 years detention should be handed down, with a finding that some offences are "particularly heinous".
The armed boys acted as a joint force, not leaving when they were given the opportunity or taking car keys that were offered, Mr Finch said on the second day of a sentencing hearing.
"They are both involved up to their eyeballs ... in terms of inflicting violence on the household".
The court had heard Mrs Kefu woke about 3am to the sound of car doors before finding the boys inside the home.
They demanded car keys, telling Mrs Kefu to "f**king shut up" and threatening to kill her.
Woken by his wife's screams Mr Kefu told the teens to leave, with the couple gesturing to car keys in a bowl.
Asked what stopped the teens from retreating, defence barrister Laura Reece said: "fear, confusion, intoxication and immaturity".
The confrontation that followed lasted a short time in which there was screaming and Mr Kefu charged at the intoxicated 15-year-old boys with a bar stool, Ms Reece told the court.
"This was reactive violence to a situation, absolutely created by themselves, but one which was borne of panic - it was essentially fighting their way out of a situation they had created for themselves," she said.
Before the teens got to the Kefu's house they had stolen a litre of whiskey after drinking earlier and their offending was reactive rather than a conscious decision to stay and hurt people, defence barrister Daniel Caruana said.
One teen, who was born in a refugee camp, asked his barrister to tell the court he apologised for the trauma and permanent damage done to the victims.
"He has imagined to himself the family's experience and he knows it was serious and miserable," Ms Reece said.
"He knows he has caused terrible trauma and is truly sorry for the unfixable scars, the hours of surgery and therapy they've endured."
The defence barristers argued for their clients to receive a sentence of about six years in detention of which they would only serve half, saying they had good prospects of rehabilitation.
Both boys have been in detention for about 1000 days.
Justice Davis will hand down the sentence on a date to be decided.
