The finding, which has this month been released to the Bay of Plenty Times, said police spoke to the driver. No charges were laid.
Matenga said both drivers felt they had right of way. There was no collision.
Hawkins drove to his home behind the other driver who was travelling to his home nearby, the finding said.
Hawkins pulled into his own driveway and the other driver stopped. Hawkins argued while standing in his driveway while the other driver argued while sitting in his car.
A neighbour witnessed the argument and told police the other driver, who was a much younger man, did not get out of his car, the finding said.
Matenga said a post mortem examination showed the death was due to natural causes being a myocardial infarction due to coronary artery disease.
Pam Hawkins told the Bay of Plenty Times she understood the driver of the vehicle "burst into tears" when police told him Hawkins had died.
She said no doubt he would have felt terrible about the outcome and it was a good lesson for people to "think first" before launching into an upsetting situation.
"He was only a young man and that's something he has to live with now for several years.
"It sounds like the old arteries were going anyway but he could have lasted a couple more years."
She said she had decided to "put a line under it" and move on with the memories of their 53-year-old marriage. They had one daughter together.
"I can't forgive him (the driver) but I can try and forget. I might move on but I feel like he robbed me of a couple of years with him."
She said she hadn't heard from the driver and probably didn't want to.
She was adamant her husband indicated correctly and the driver of the other vehicle didn't see it and went on to the roundabout, nearly hitting the passenger side of their car.
"I'm just grateful he had good brakes because otherwise I would have been a goner."
She said the past 16 months had been a big adjustment as her husband was also her main carer, as a result of her being on crutches following cancer treatment.
After living at the same house together for 20 years, she had now decided to sell it because it had become too big for her to manage on her own.
"I'm well looked after now by other carers but part of me misses having a bloke around."