After coming home from the supermarket on Friday night, Penny Keegan received a phone call every mother dreads.

Her 15-year-old son, John, was a passenger in his friend’s ute during a “very minor” collision, when the Toyota rear-ended a BMW waiting to turn right off the Mitchell Highway near Orange in central-western NSW.

But, when he got out of the car to check on the 70-year-old occupants of the BMW, both cars were hit by a prime mover coming in the other direction.

John died at the scene.

That same night, his grandmother also passed away following a battle with dementia.

Penny told 7NEWS that she wasn’t surprised by the reports saying her eldest son had gotten out of the car to check on the couple in the other vehicle.

“I just think he was so amazing, but I know I’m biased,” the mother-of-six said.

“John was cheeky, he was naughty – not bad, never bad naughty – he would get in trouble at school for pranks and silly things.

“He was loved by everyone, even the teachers.”

Penny recalled a time John told off one of his younger brothers who had been teasing his sister and calling her names.

“John went outside and said, ‘listen here mate, I don’t want to hear you ever speak to your sister like that ever again. Never speak to girls like that’. It was just gorgeous,” she said.

“He’s dead set the coolest kid.”

After caring for her mother for the past week, Penny left her mother’s bedside and received a call from John asking whether it would be OK for his friend to pick him up, and go to his house to stay. She agreed.

It wasn’t until she had returned home from the supermarket that she received another call, this time from John’s friend.

“Penny, I’m so sorry we’ve had an accident,” he said.

“I said, ‘where are you darling? We’ll come and get you’, just thinking they were bogged or something I don’t know,” Penny explained.

“He said there were a lot of people there … ‘it’s really bad’. It was just a horrible nightmare.”

When Penny and her husband Jason rushed down to the scene of the crash, police wouldn’t let them through.

“We went out to the hospital and we waited almost an hour before they actually came and told us,” she said.

The couple then had to pass the news onto the rest of their children.

“I think the most important thing is we stick together and stay strong,” she said.

But, just 20 minutes later, she received a phone call from her dad.

“He said, ‘hey love, look I just wanted you to know your mother’s just passed’ and I had to tell him his grandson had as well and he was distraught,” she said.

“We’re all distraught. I can’t make rhyme or reason of this.”

A GoFundMe page has since been set up to help with the costs of both funerals.

Acting Inspector Josh Dixon told reporters on Saturday that the initial collision was “very minor”.

“The [boy] was trying to do the right thing, absolutely,” he said. “It’s absolutely tragic that this is the result.”

The 17-year-old ute driver and the couple in the BMW were taken to Orange Hospital in a serious but stable condition.

The truck driver was taken for mandatory testing but released pending further inquiries.

Police are investigating the incident, and a report will be prepared for the coroner.

Image: 7NEWS