Joining the Kangaroo March to Sydney, the brothers left behind four sisters, a brother, and their parents.

With little correspondence from the battlefield, it would be four long years before they would know the brothers' fate.

Stationed with the 55th Battalion, Edward and Charlie saw the worst of the fight on the Western Front.

They were among the few who returned home in 1919, after their time at Fromelles, the Somme, Ypres and Passchendaele.

"About 2000 or 3000 men died the same night [Charlie and Edward] arrived on the battlefield," said Edward's son, Michael Fitzgerald.

It was a far cry from the lives they had measured out in Wagga, where Charlie had worked as a carpenter, and Edward as a bricklayer.

"All the young fellas of their day thought it'd be a picnic, just a few weeks away and they'd be home with the tales," Mr Fitzgerald said.

The world that confronted their battlefield arrival in July 1915 was one crafted of the unimaginable.

The mud of the trenches hid the masses of decomposing bodies, laying wherever their lives had been seized.

Rats, lice and disease covered the inches between the barrage of bullets.

"Dad was lucky it's fair to say, he was never wounded. But he always had bad feet," Mr Fitzgerald said.

"Mum would say he couldn't bear for the blanket to touch his feet in bed. Trench foot, I suppose, caused by months standing in three-foot of freezing, filthy water."

Though he rarely spoke of his years on the front, fortune favoured Mr Fitzgerald's father in body and mind.

Both Charlie and Edward returned home to Wagga with barring little evidence of the psychological trauma they had encountered.

"They fought together, and I imagine they'd have become very close," Mr Fitzgerald said.

"Friendships forged in that environment were like that."

Like many young men in the First World War, Edward had falsified his way to the fight.

"Dad tried to enlist in Wagga before the march came through," Mr Fitzgerald said.

"He was knocked back because he was blind in one eye. But holding a gun was nothing for him, he was off a farm, he knew he could do it.

"So he joined the march all the way to Sydney."

During his medical test, Edward was asked to cover his right eye with his right hand and read a line of text. He was then asked to repeat the motion, using his left hand to cover his left eye.

Instead, he slid his left hand over his right eye and read the text perfectly. A moment's distraction caught the doctor's attention, and Edward passed the exam.

Although it is a tale that has been well-known in Mr Fitzgerald's family for many years, he was confronted with its sheer significance when, in 2015, Mr Fitzgerald joined the Kangaroo March commemoration.

"It really occurred to me, he was so determined to go," Mr Fitzgerald said.

The only first-generation descendant of a World War I veteran on the march, Mr Fitzgerald admits he was less than willing to join the gruelling 35-day journey.

"When I started [the march] I didn't intend to finish," he said.

"I thought I'd get to a point and stop. But I kept going. It was physically challenging but absolutely fabulous."

Each step of the 500-kilometre trip brought Mr Fitzgerald to understand the man he had tragically hardly known.

"[My father] was killed in a car accident when I was four," Mr Fitzgerald said.

"He survived the war, and the depression, and died so suddenly a couple of years after World War II finished. Not much of a life, is it?"

Mr Fitzgerald's youth dealt a waxing memory of his war-hero father. But the five-week march from Wagga to Sydney re-invigorated his familial connection.

"That experience - walking in my dad's very footsteps - it was an honour, frankly."