'I called my brother after spreading our dad's ashes. Hours later, the police were at our door.'

Baci Hillyer's world didn't end gradually; it blew up in a six-month flash.

First, at 15, her father — the man she idolised her entire life — became unrecognisable when brain surgery to remove cancerous tumours left him a different man. Within months, Baci was forced to say a final goodbye.

Just five months later, it was Baci's brother, killed by two semi-trailers on the highway home from scattering their father's ashes.

As if that weren't enough, Baci watched her mother execute an "existential death," becoming so overcome by grief she was incapable of being a parent.

Baci was left, a teenage girl profoundly and impossibly alone.

Watch: How to deal with the loss of a loved one. Post continues below.

The first sign of the collapse came near Father's Day when Baci was just 14.

"I found [my dad] having a seizure on the floor," she told Mamamia.

"To see my hero, blue on the floor, shaking like that was really traumatic."

Within two weeks, the diagnosis arrived: two cancerous brain tumours that needed emergency surgery.

For Baci, the "daddy's girl" who wore the Kmart PJs proclaiming, "My heart belongs to daddy," the loss was unimaginable.

Surgery was necessary, but it stole the father Baci once knew. He emerged as a different man.

"For me, the person who came out of the operation was not my dad," she said.

"He was never the same again."

Baci turned 15 in December; by March, her father was gone.

Baci (far right) with her siblings and father. Image: Supplied.

Six months later, the family was still reeling from financial and emotional disarray. Her mother was "a mess."

Baci's brother and mum flew to the family farm to scatter the ashes. Her brother planned to drive back the next morning.

Baci's last conversation with him is forever etched in her memory. She called him that night, and, knowing he'd met a girl on a recent holiday, Baci "stupidly" told him that she'd called.

He immediately decided to drive home.

It was on that late-night drive home that he fell asleep at the wheel and was hit by two semi-trailers.

Baci and her brother. Image: Supplied.

For years, Baci was wracked with grief, believing her casual comment caused his death.

Years later, she learned her brother's intended hosts admitted they were having relationship struggles and her brother just wanted to leave.

Early the next morning, police arrived. Her brother was dead.

Aged just 15 and 17, Baci and her sister had to identify their brother's body after being flown to the morgue.

"It was terrible," she said. "That sort of scarred me for life."

Baci's once safe, comforting family unit had been completely destroyed.

Baci (right) with her mother. Image: Supplied.

Then she watched her mother slowly disappear.

"She was never the same," Baci said.

"Her role as a wife was gone, her role as my mother was gone — she wasn't really capable of fulfilling that.

"My whole life crumbled within six months. I lost my whole family."

Her mother's boss stepped in to take care of them — a wish expressed by Baci's father.

But this wasn't the support she needed. Instead, Baci says, he whisked her mother off to a health retreat in Switzerland, leaving 16-year-old Baci home alone with his housemaid.

"All of Year 11 I was alone. I was in deep grief," she said. "It really f***ed me up for a long time."

With money left to her, Baci coped the only way she knew how: the house became the Year 11 party house; the year was a blur of noise and distraction.

She survived by numbing herself, yet every morning, she still managed to drag herself out of bed and into the one stable place left: school.

Baci struggled with losing her once-close family unit. Image: Supplied.

The harrowing, lonely year passed, and Baci emerged through the other side. She learned to live with the truth that grief isn't something you get over, but something that evolves.

"Because I've grief-walked 37 years, it's 70 per cent of my life, I almost don't know any different," she said.

"Grief is your greatest teacher. Then you get to reflect and really learn your lessons later."

Today, Baci is a death literacy advocate. Image: Supplied.

Today, aged 52, Baci hasn't stopped tending to loss.

Her childhood trauma gave way to a powerful life's work: she is now a death literacy advocate and end-of-life doula — someone who provides support to families during the dying process and after.

She dedicates her life to helping others be ready for when loss comes knocking, understanding that the experience is "deeply personal."

Baci knows survival is possible, but it starts with acknowledging the full, messy weight of the loss, something her family was never able to do — but something she can help others achieve.

Feature image: Supplied.