Singh understood his brother, a healthcare worker, had been on the way home from a night shift when the crash happened.
Singh said he last spoke to his brother two days ago.
"He was really happy. He had a good job. He was making good money.
"Everything was going good for him and he was about to become a father."
Singh said Jabbal's girlfriend in New Zealand was due to have a baby boy - to be named Parminder Junior - in October.
"He was happy to become a father."
She broke the news to the family in an early-morning phone call yesterday.
"We never expected this. We don't know what happened that night."
Singh said he and his father had not told Jabbal's mother her son had died.
"We have told her he is in hospital. She won't be able to take it."
He said the family was making arrangements through a funeral director to bring Jabbal's body back to India, but it would likely take 10 to 12 days.
"We want to perform his last rites here in India."
The family would invite his girlfriend to come too but understood she may not be able to fly.
"We are asking her to come here so we can look after her."
Singh said Jabbal was the eldest of three children and came from the city of Ludhiana in the Indian state of Punjab.
He came to New Zealand in May 2016 to study healthcare management.
The course was a year long and Singh said his brother, a calm, happy and hard-working man of few words, quickly found work after and settled down.
He got his work visa four months ago.
He had not been home to India since coming to New Zealand, but Singh believed his brother had been making plans to visit when his son was born.