When Patrizia's son died on a construction site, she sped to her two sons. It was too late.

“The pain is like a roller coaster without breaks. It has high points and low points, it just doesn’t stop, and this is my life sentence.”

Losing a child is, as Patrizia Cassaniti’s doctor told her, one of the most horrible things a human can go through.

But Patrizia’s bond with her Christopher is unique. One many mums stare into their newborn’s eyes and hope for their future selves.

Here is Christopher and his parents. Post continues after video.

He was far from the 18-year-old stereotype that grumbles, refuses to set the table, and only addresses his parents when there’s dinner involved.

He was generous, kind, and willing to drop anything (even his beloved Xbox) to be by her side.

In the year and a half before Christopher’s death, Patrizia and her son spent every working day intertwined.

She ran a coffee van. He was an apprentice tradie.

Every morning, they'd ride to Sydney's Macquarie Park together and she'd fill the cups of his colleagues before they'd all trudge onto the worksite.

Anytime there was a lunch break, a smoko, or even just a chance to stretch their legs between duties - Christopher was back at the van with his mum.

"He'd hug me on the job site," Patrizia told Mamamia. "I'd say to him 'Christopher, there are people watching you' and he'd say 'I don't care.'"

"They used to call him the luckiest boy on site," she remembered fondly.

With his mum within metres of him, Christopher had a hand delivered breakfast, lunch and afternoon tea before they'd make the trip home together at the end of the day. He knew how lucky he was.

"He'd have a smile ear to ear while the boys would banter with him about not having to pay," she said.

Sometimes Patrizia would hear the workers complaining about things they hadn't found to be particularly 'safe'. She didn't think anything of it. Why would she? Everybody vents about work.

Little did she know, the construction company Ganellen had been getting warnings about its scaffolding being unsafe for about a year.

In some of the emails, the scaffolding company had warned that tampering breaches were putting lives at risk.

Things like too much building material overloading the structures and the premature removal of ties from the buildings they were being held up by.

Three safety officers had resigned throughout the course of the job.

On Monday April 1 2019, Patrizia didn't join her son in their daily routine.

Christopher had celebrated his 18th birthday on the weekend, and she was tired.

"I'm not going to work tomorrow," she told him the night before, as he sat with her and her husband, Rob, on the couch. A rare occurrence, given he usually spent the evenings in his room playing Xbox.

"What will I do for lunch though?" he'd asked her, while he gave her a hug, a moment Patrizia now treasures among one of her best.

"You'll figure it out," she laughed.

By midday the next day, Christopher was dead.

He was crushed by 17 metres worth of scaffolding, and in his last words he screamed out for his mum.

Patrizia is glad she wasn't at work that day.

"I don't think I would have survived it," she admitted to Mamamia.

When she learnt of the accident, she immediately made her way there.

"As I got closer and closer, I couldn't breathe. I prayed the whole way thinking he'll be fine... he's a strong boy... there are 1000 workers there.. it's not him.

"When the policeman knelt down in front of me and looked up at me, I knew something was wrong. I started shaking my head.

"I'm sorry Mrs Cassaniti there was nothing we could have done for your son. Unfortunately he has passed away," she heard him say.

Patrizia said she screamed, and then continued screaming.

"He's just turned 18, he has a strong heart, he's just unconscious," she told them.

They shook their heads.

Patrizia remembers every single second of that encounter. It was the worst day of her life. But the terror wasn't over.

"The police told me I had to move quickly. They told me media had his name," she explained.

Christopher was a middle child, and Patrizia sped home to protect her two other sons. But the 20 and 16-year-olds had sat on the couch watching a newsreader inform them of their brother's death.

"I am so angry they found out that way. Both of my sons still aren't dealing with it. I can't even get them to talk," she said.

Seven weeks on, the only thing that helps are the family trips to the Hawkesbury river. They'd only recently started teaching all three boys to water ski there.

"It's where we feel closest to Christopher," Patrizia said.

3000 people joined the Cassaniti family at Christopher's funeral.

"He touched so many lives on that Monday, my phone nearly exploded. Even now, every time I open my Facebook messenger there are thousands of messages from people," she told Mamamia.

Patrizia and Rob are funnelling their grief into fighting for Christopher's Law.

It's to give workers assurances that they have the right to remove themselves from an unsafe situation if they feel like they are in danger, without fear of persecution.

The couple also want industrial manslaughter charges brought into New South Wales like the ones already in place in Victoria and Queensland.

These two goals are Patrizia's life purpose now.

"I am very angry, but my anger isn't going to bring my son back. All I can do is make sure he didn't die in vain.

"That my beautiful son with the most beautiful smile is not going to be forgotten. I am not putting this under the carpet."

The coffee van hasn't been touched since Christopher's death. Patrizia can't even bear to look at it.

"To go back into the van.... it's empty. It's an empty feeling," she said.

While she knows she'll never do a coffee run again, Patrizia will never forget the year and a half she got to be with him making memories.

Just son and mum, hanging out in an Xpresso mobile coffee van.