"We didn't expect her to go through something as serious as this at her age. We don't know what's going to happen."
Mr Rebello believed his mother-in-law had thought the car would stop before walking over the crossing.
He went to the scene soon after and saw the young male driver of the vehicle talking to police.
The whole family was "traumatised" by what had happened, Mr Rebello said.
"Her husband is 80 years old and has diabetes. We've told him it was just a minor accident because we're worried about stressing him.
"My sister-in-law lives with him and is really worried. My wife has taken unpaid leave from work to look after everyone.
"We need people's prayers at this difficult time."
Mr Rebello told the Herald he had been advocating for improved safety for pedestrians on Mt Albert Rd for eight years.
"I've been to my local board; I've been to the council; I've been to Auckland Transport.
"It's a busy area. I've seen lots of crashes and near crashes over the years, and there's boy racers that race up and down the road.
"There should be traffic lights at that crossing."
An Auckland City police spokeswoman said police investigations into the incident were continuing.
An Auckland Transport spokesman said it was working with the police serious crash unit on its investigation.
The pedestrian crossing was put in in 2014, replacing a pedestrian island on the road.
