The youths faced Brisbane Children's Court on Thursday for sentencing after pleading guilty to seven charges committed when they were aged 13 and 15 including intentionally causing grievous bodily harm and unlawful wounding.
Judge Ian Dearden said the aftermath of the attacks was one of the worst he had seen in his long career.
"I cannot cope with looking at photographs (of the crime scene) ... there is more blood there than I ever want to see in my life," he said.
Kefu suffered critical wounds to his abdomen while trying to defend his family in the early morning attack at the inner-Brisbane suburb of Coorparoo on August 16, 2021.
His wife and 21-year-old son also suffered serious wounds and his 18-year-old daughter was injured while wrestling with the intruders.
Both youths did not enter the Kefu family home but were charged with violent offences as they knew their two older co-offenders had weapons and were prepared to use them.
The 13-year-old was on bail at the time for burglaries and car thefts and went on to commit 19 similar offences after the attack on the Kefu family.
The 15-year-old was on probation at the time of the home invasion.
Crown prosecutor Nathan Crane said the four co-offenders had decided, in their words, to go out "creeping" to find cars to steal and later use in street racing at the Gold Coast.
"They weren't naive, there was a plan to creep," Mr Crane said.
Mr Crane said the four teens had already taken part in a home burglary and car theft on the same early morning as the home invasion.
During that earlier burglary, they were confronted by a woman who grabbed on to the side mirror and told them to "get the f*** out of my car".
"There was forewarning that they could be confronted by people who had homes entered," Mr Crane said.
While driving to the Kefu family's home, the 15-year-old boy heard one of the other boys say "if someone wakes up, just stab them".
Mr Crane said both boys must have seen the large cane-cutting sickle carried by the other co-offenders and saw them use a knife to damage the interior of the car.
The 15-year-old's barrister Edwin Whitton said the only evidence to support the serious violence charges was his client telling police he heard an older boy talk about stabbing.
"He was not aware of the horrors transpiring in the home," he said.
Mr Whitton said his client was from a disadvantaged background, was intoxicated at the time and his only intent was to steal cars.
The 13-year-old's barrister, Scott Carter, said the only appropriate sentence for his client was one of detention and the only question was for how long.
"I would propose two-and- a-half years … (the boy) is remorseful," he said.
Judge Dearden said the only difference between the two boys was their age given their similar levels of involvement and prior knowledge that violence could be used.
"You were both intoxicated, you both did not go inside the house," he said.
Judge Dearden said there had been a substantial benefit to the victims and the community from the boys pleading guilty.
Youths invaded the Kefu family's home while armed with at least two bladed weapons. (Dan Peled/AAP PHOTOS)
Both boys were sentenced to detention orders of two years and six months with a 50 per cent minimum to be served with no convictions recorded.
The 15-year-old was released with 464 days time served.
"I hope for both of you after committing these awful, ghastly and dreadful offences that you not reoffend, that you make your families proud," Judge Dearden said.
The two youths who entered the home and attacked the Kefu family are due to be sentenced in May.
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