When Hugh Poate sees the couple disappear on a trail bike on the Poates' bush block he almost can't hold back his tears. "It's just beautiful," he says.

At first Hugh and Janny Poate could not walk through the gate to their block, after losing their son. Too many memories of Robbie, who was killed by a rogue allied soldier in Afghanistan, overwhelmed them.

Now traumatised soldiers go there to help rebuild their lives and learn how to love again. They are the Poates' family.

The commando on the bike has a cracked vertebrae. He's traumatised after seeing his best mate blown into pieces 30 metres in front of him in Afghanistan.

Mr Poate has seen other women with husbands like this one, bursting to help them. "They want their husbands back that they fell in love with and married," he says.

"On the bike, they cuddle in, they put their faith in the guy. They may never have been on a bike before. They adore the guy and want to help."

Thirty years ago the Poates bought their block 10 kilometres from Gundaroo and called it "Sweleena" after the black mare Hugh rode on his parents' sheep and cattle farm at Tumut when he was a boy.

Sweleena was for Robbie and their daughter Nicola to grow up in the bush as they had, to experience a yabby in the dam tug on their piece of string and meat, to trap rabbits and, with schoolmates, build and sail rafts in the dam, which later was stocked with trout and yellow belly perch.

"Robbie loved this place," says Mrs Poate. "He would come down here whenever he could to his vineyard which he created. Robbie did various agricultural courses at school. He guided Hugh on what to prune and when to prune it.

On ABC's Four Corners on Monday night, Afghan National Army Sergeant Hekmatullah gave not one shred of light on why he killed Private Poate and his two mates in August, 2012, as far as the Poates are concerned.

Time will never erase that senseless betrayal, of firing 26 rounds on them as they relaxed at patrol base.

A breeze ripples across Sweleena's big dam and ruffles roses in the nearby "Robbie Garden" which friends gave them after their loss.

"The first time we came back out here (after his death) we got to the front gate and burst into tears, and went back home" Mr Poate said.

They could nearly see Robbie come through that gate and go straight to his merlot, shiraz and cabinet savignon vines. They remembered looking down from the verandah deck to the big dam. And the bay trees framing the timber steps to the deck, where fairy wrens nested and grew bolder, flitting about closer and closer to the Poates.

Robbie said to his mother one day: "Don't you and Dad ever sell this place because I want to bring my wife and children out here."

Sweleena will always be held in a trust for war-weary soldiers, like the shaken one who recently remarked: "Janny is a mum without the hassles."

Mr Poate said Robbie had perfect hand-eye coordination which made him an excellent motorbike rider. He loved to jump his Honda XR over the dam wall and throw the back wheel into broadsides.

After the returned, injured commando got on the bike with his wife at Sweleena they were away a long while, so much so Mr Poate reassured himself they were OK. Turns out they had found another dam.

A smile on his face on his return, the soldier said: "We went for a skinny dip."

A green oasis in the scrubby bushland, Sweleena's yellow iris, lavender and tangle of sweat pea bloom under silver birches and Japanese maples.

Mr Poate mows and clears dead sticks. Mrs Poate sighs at a mounting list of jobs she needs to do in what has become a shrine around the Robbie Garden and its plaque which reads:

Death leaves a heartache no one can heal

Love leaves memories no one can steal

This garden is dedicated to the loving memory of Robert Hugh Frederick Poate

15.11.88 – 29-8-12.

Soldier killed in Afghanistan

Rest in peace.

Lest We Forget.