Brendon fled to a nearby home where his aunt and uncle, Jan and John Boyd, were staying with Jan Boyd's daughter Georgina Langford.
Soon after, Ian Boyd arrived at the house brandishing a shotgun and demanding to see Brendon.
Georgina wrestled with him as he pushed past the family and shot his son in the right side of his chest from about "six paces" away.
Brendon fled to a bathroom, where Jan Boyd, a registered nurse , put pressure on his wound and held it there for an hour as she waited for emergency services to arrive.
Meanwhile, a bedridden John Boyd told Georgina to flee the house and called the police.
Ian Boyd pointed his gun John, telling him to get off the phone, ranting about "my own brother selling me to the cops" and telling him he wanted to "finish off" Brendon.
He then abruptly left the property. Soon after he called his wife Michelle to tell her: "I'm going to die tonight. These are the final words I'll have with you."
Ian Boyd had a brief conversation with police sergeant Wade Jennings at 3.16am.
In the phone call he acknowledged he had responded badly to two people trying to kill him and said "I have no options, I'm not going to die in jail".
Within 10 minutes of the call, Boyd drove through a police checkpoint.
At 4.12am, as armed police approached his van, he shot himself in the head with a shotgun.
Ms na Nagara said the events that led to Boyd's death were set in motion by his paranoid delusion that Brendon and his stepson Heath Boyd had come to his house to assault him.
Ian Boyd had a history of mental illness - though he had never been considered a threat to his family before the events of April 21, her findings said.
"Obviously we know now where Ian's paranoia was to lead, but on the evidence before me I do not think it reasonable to say his terrible actions that night could have been anticipated by those around him."
Ms Na Nagara's findings concluded by praising the "extraordinary courage and composure" of John and Jan Boyd and Georgina Langford.
She said their response to a situation of "abject terror" was brave and selfless.
"Georgina's grappling with Ian to get the gun off him, John's engagement with Ian in an effort to keep him from the others and Jan's first aid efforts which almost certainly saved Brendon's life reflect a selfless disregard for their own safety and a level of courage that was remarkable and should be commended."
Where to get help:
* Youthline: Support for young people and their families; youthline.co.nz, 0800 376 633
* Kidsline: Phone counselling for children aged 9 to 13; kidsline.org.nz, 0800 543 754 (4pm to 6pm weekdays)
* Whatsup: Counselling for children aged 5-18; whatsup.co.nz, 0800 942 8787 (noon to midnight)
* The Word: Questions answered about sex, life and relationships; theword.org.nz
* Depression Helpline: Counsellors who can find the right support for you; depression.org.nz. 0800 111 757 (8am to midnight)
- HERALD ONLINE