West, 34, said they didn't have all the details about what happened to his younger brother but had been told he was hit by a car while walking home from a New Year's Eve party.
Queensland Police said in a statement about 3am a 22-year-old man was standing on the road when he was struck by a car.
The driver swerved to avoid him and had a minor collision with another vehicle. Both drivers were uninjured.
Hayward was rushed to hospital with life-threatening injuries and his some of his family have flown to be by his bedside.
But his condition was still critical and it was not looking good, West said.
"They're looking at turning off his life support today," he told the Herald.
Hayward, who grew up in Rotorua, had just moved to Brisbane to live with his older sister after struggling to get over the death of his cousin and best friend, Hendrix Hayward, who died in August in 2016.
Hayward was living with his cousins, including Hendrix, and his aunt in Perth when his cousin fell off his skateboard while being towed by a car, known as "skitching".
Hendrix was taken to hospital in a critical condition and later died after his family had to turn off life support.
West said it was a "crazy" something similar happened to Hayward.
"It hit him really hard when my cousin died. It turned my brother into a depression.
"He never really recovered from it and it's so crazy that it would happen to him a few years later."
West said Hayward's accident would hit his family both emotionally and financially as his step-mother had to borrow money to fly to Australia to be by her son's bedside.
He's set up a GoFundMe page to raise money to help cover the costs as if the worst transpires, they'll need to look at bringing Hayward's body back to New Zealand as well as funeral costs.
West doesn't want his family members to go into debt to do this.
"I feel pretty helpless here in New Zealand and I thought that would be the one thing I could do to help people."
So far, more than $1600 has been raised in less than 24 hours.
West, who lives in Bali but is back in New Zealand for Christmas, said he's grateful for everyone "coming together to help".
Despite living overseas, West said he and his brother were close because they are quite similar and keep in touch online.
He's flying to Australia tomorrow to be with his brother.
"We're going through waves of emotions and the hardest is yet to come."
