Former Brothers for Life heavyweight Farhad Qaumi has been sentenced to 60 years behind bars and his brothers will spend decades in prison for their roles in a violent gangland war. 

The Qaumi brothers were part of the gang's Blacktown chapter when it was embroiled in a brutal war with the rival Bankstown group in 2013. 

The Qaumis were convicted after a mega-trial in the NSW Supreme Court last year over a string of high-profile crimes. 

Those included the killing of Mahmoud Hamzy in Revesby Heights, shooting with intent to murder BFL member Michael Odisho and shooting a teenage girl.

Farhad and Mumtaz, 31, were also found guilty of organising the murder of debt collector Joe Antoun at his Strathfield home in December 2013.

Farhad, the "undisputed and feared" Blacktown chapter leader, was sentenced in the NSW Supreme Court on Friday to 60 years' jail with a non-parole period of 43 years.

Justice Peter Hamill said Farhad would be about 75 when he was eligible for parole but could only be released if he no longer posed a danger to the community. 

Mumtaz, the second-in-charge, was sentenced to 50 years behind bars but will be eligible for parole after he has spent 36 years in jail. 

Jamil Qaumi, was convicted of 18 offences and sentenced to 30 years' jail with a non-parole period of 21 years. 

The brothers, who came to Australia as refugees in the 1990s, were led out of the court dock one by one, patting each other on the arm as they left. 

In delivering his sentence over three hours on Friday, Justice Hamill detailed the brutal gangland war in which the crimes were carried out.

He found many people were exposed to the violence.

"Many people's lives have been affected by the outlandish and lawless violence in which these offenders were involved in a two- to three-month period in the latter part of 2013," he said.

Mahmoud Hamzy was shot three times in the head at close range when gunmen turned up at his family home in Revesby Heights on October 29, 2013.

The court heard the plan was to kill his cousin - Mohamed Hamzy - the leader of the Bankstown BFL chapter - who was at the house at the time but escaped the gunfire.

There was a general belief among the offenders that Mohamed had to be killed to protect the life of Farhad Qaumi. 

Mumtaz and Farhad Qaumi, who went to a club in Merrylands to give themselves an alibi while the shooting was carried out, and Jamil were convicted of conspiracy to murder and manslaughter.

They were also convicted of causing grievous bodily harm to Omar Ajaj, who was shot but survived.

Over the next several days, three other shootings were carried out as the Blacktown chapter feared the Bankstown group would seek retribution.

 A teenager girl was caught in the crossfire and a number of "lives were put in peril", Justice Hamill said. 

Bankstown BLF member Michael Odisho was shot when he answered the door of his Winston Hills home on November 3, 2013. He survived.

The court heard the failed shooting angered Farhad, who told fellow gang members the following day, "How hard is it to shoot someone?"

The next day, gunmen opened fire at the Blacktown home of another man, a low-ranking gang member, but ended up shooting a his 13-year-old sister in the back instead. 

"[The teen] was left with devastating injuries," Justice Hamill said. 

"Her capacity to become pregnant and carry a baby to full term is compromised."

Days later, Abdul Abu-Mahmoud was shot outside the Chokolatta cafe in Bankstown.

He was associated with members of the Bankstown BFL and Mumtaz feared he had access to the addresses of his Blacktown chapter members. 

Just after midnight on November 7, Mr Abu-Mahmoud's car was stormed by gunmen armed with machineguns, firing through its windows so ferociously they destroyed a headrest.

Miraculously, the three men inside survived.

Farhad was not involved in the Chokolatta cafe shooting.

Justice Hamill said these shootings formed part of a violent gangland war in which some casualties were innocent victims. 

In December 2013, Farhad and Mumtaz accepted a contract - up to $100,000 - to kill Mr Antoun. 

The pair organised another man to go to Mr Antoun's house and shoot the father-of-two in a "cold-blooded murder". His wife was home at the time and cradled Mr Antoun in a pool of blood until the ambulance arrived. 

"The impact on the family is unfathomable," Justice Hamill said.

Jamil was not involved in the Antoun shooting. 

Justice Hamill reflected on the brothers' traumatic upbringing in war-torn Afghanistan before they moved to Australia.

Their mother said in a letter to the court her children were subjected to "horrifying conditions" for 10 years and the effects of war plagued them even when they moved to Sydney.