Family are now rallying around the heartbroken widower, who also has heart issues.
Mark Houghton, the couple's son, says his Hamilton-based sister, Niki, went their parents' house at first light.
He says his mother was in good spirits and was even looking forward to doing renovations.
"We've been talking to Dad over the past couple of days, and Mum was was almost excited about having to re-model the living room and put new carpet in and curtains and told him 'we're going to do it [renovations] my way, Gary'."
However, the family believe the crash was a factor in her death.
"We all believe that the incident that happened on Sunday morning was a trigger because Mum did have a heart attack on late Sunday afternoon," Mark Houghton said. "It didn't cause it but the stress and shock of it probably just caught up with her."
He says his 72-year-old mother had an underlying health issue and she had just come out of hospital after spending eight days there with heart problems.
"So we knew that Mum's heart wasn't very strong. We also knew that if she did have any other events that there was no surgical procedure that would be able to remedy it."
However, she had been in high spirits since her release and the couple, who had celebrated their 51st wedding anniversary two weeks before Mrs Houghton's death, were looking forward to doing some travelling.
"She knew she wasn't well and she knew that she wasn't going to have the capacity that she's had in the past but she was optimistic and looking forward to what time she had left. She was incredibly active and walked every second day, so it wasn't holding her back in that respect. And then there was the crash and attack."
Police have confirmed they are investigating whether any further charges should be laid against the 15-year-old.
But for now, the Houghton siblings were worried about their dad, who had a quadruple bypass 15 years ago.
"He's still got blockages so his circulation isn't great. He's just managing it," Mark Houghton said.
In the meantime, their other brother, Stuart, had arrived from South Africa, and planned to stay with their father for the next few weeks as repairs are carried out on the house.
The couple have lived in the Waikato their whole lives and have a strong faith. The church is their mainstay, he says.
Mrs Houghton will be farewelled at the Horsham Downs Community Hall tomorrow afternoon.