"My grandparents put so much into Christmas," he said. "They wanted to make it special - they loved having us grandkids to spoil. But Christmas must have hurt so much for them, and my Dad.
"We grew up with this great joy that Dad had survived, but also this incredible grief and sorrow that he'd lost his mates."
At 10.21pm that night, a Wellington to Auckland night express train careened from a lahar-damaged bridge, plunging into the flooded Whangaehu River at Tangiwai, near Waiouru.
The accident, one of the nation's deadliest peacetime disasters, claimed 151 lives.
Ted Brett, 17 at the time, was in one of the carriages that went into the river, and he was able to smash through the carriage window and fight through miles of silt, mud and diesel fuel to safety.
His father's survival was a family legend - but Mr Brett said Ted - who died in 2008 - seldom spoke of his ordeal.
"The Tangiwai disaster was always just there - but it was never a general topic of conversation," he said.
"Dad was like the guys who went off to war, who came back and never talked about it. (The disaster) came back to haunt him for years. Mum said he had nightmares.
"If people tried to broach it, he'd change the subject. He just wanted to shut it out."
Later in life, Mr Brett found out more of the story.
He learned that John and Douglas Cockburn were travelling to Auckland to spend Christmas with their grandfather and Ted, "the best mate", had been invited to tag along.
When the train approached the Whangaehu bridge at 10.21pm, Ted was the only one in his carriage awake, which may have improved his chances of survival. "He'd stayed up to take some pictures of Mt Ruapehu by moonlight.
"He was obsessed with cameras and film - he had one of those old 8mm cameras."
After the accident, Ted shared his story with the Wairarapa Times-Age and described what happened when his carriage hit the water.
"The first thing I knew was that the carriage was full of water and diesel oil - I went under and got two mouthfuls," said the young man. "When I surfaced again, my head ... struck a window. I made up my mind then that I was going to get out. I smashed the window with my fist."
Ted was "thrown clean out of the window" by the current, and was carried downstream.
He found himself "halfway up a tree", holding a 3-year-old boy who he sang to while they waited to be rescued.
The force of the water had torn the clothes from his body, leaving him with only his wristwatch, his belt and his back trouser pocket, containing a 10-shilling note.
Later, 12-year-old Douglas' body was recovered - but 17-year-old John was never found. "They found his wallet under the engine tender," said Mr Brett. "Make of that what you will."
Ted was "determined to get on with life" after Tangiwai. He trained as a plumber and gasfitter, eventually starting a business with his wife, Patricia, and continued his favourite pursuits, such as hiking and rabbiting. But the crash had done its damage.
"Dad was allergic to diesel fuel for the rest of his life," said Mr Brett."(He couldn't) explain to his friend's parents and family why he lived and they didn't.
"I've seen pictures of my uncles, and they were just happy-go-lucky boys, enjoying the country life and making their own fun. They had a future and that was all cut short on Christmas Eve.
"Dad never caught a train again after that."
Mr Brett - who is named after the uncles he never met - remembers Ted as a "man of few words"; a hard worker who loved the outdoors and grew trophy-winning chrysanthemums.
"Dad never did anything by half measures. He was a man of deeds, not words. He lived life to the full."
He said he feels "bloody lucky" his Dad lived through this country's sixth most deadly disaster.
"God only knows how he made it out of that carriage. It was a Christmas miracle that he lived."