"Her cousin Nola was right behind her and witnessed it all. She immediately got into the car with Ngaire and comforted her until the ambulance, police and fire teams arrived."
Mike said Nola contacted the wider family immediately and "pretty much all her close family were at her bedside until she passed away at 10pm".
"She had horrific injuries, they were awful, but she didn't show any pain right through to the end. In the last few minutes, she passed away very peacefully."
Ngaire turned 80 last September and her funeral was held in Rotorua on Monday.
"It was quite a joyous funeral," Mike said.
"She was a wonderful woman to celebrate, with a pretty amazing life."
Mike wrote and read his mother's eulogy.
He said around 220 people attended, including "a lot of friends, a few from her church faith, and family".
"She had nine great-grandchildren, and 11 grandchildren who presented a lovely tribute at the funeral."
"Courageous" was the first word Mike said when asked how he described his mother.
"In her late 40s, she got her pilot's licence and started flying planes. At age 50 she decided to become a real estate agent and won awards for that. She was remarkable. Nothing stopped her."
He said Ngaire never let her "significant health issues" hold her back in later life.
"She lived alone for the last few years. She was constantly out and about," he said.
"Dad passed away four years ago so it's nice to know they are together again in the right place."
Mike said he had spoken with Ngaire's cousin Nola daily since the crash.
"It was horrific for her no doubt. I can only hope that Nola has come to grips with what she experienced firsthand ... We as a family were so grateful for Nola and the comfort she was able to provide Ngaire in her hour of greatest need."
A man was also taken to hospital with serious injuries from the crash.
The Serious Crash Unit continues to investigate it.
NZ Transport Agency transport system manager Rob Campbell said there were six crashes reported to police at that intersection last year.
"Road and roadside safety improvements are proposed for this 3.2km section of State Highway 30 from Owhata to the outskirts of Rotorua near Te Ngae."