Happy families: Julie Bullock (left) with husband Darren (centre) and twins Hudson and Sienna, 7, and other family members last year. Picture: Facebook

As Mr Bullock, 52, keeps a bedside vigil by his daughter Sienna following the terrible car crash which killed his wife, Julie and Sienna’s twin, Hudson, tributes were pouring in for the family.

Julie, 49, and Darren were a devoted couple, who told their friends that even after more than a decade and two kids together their romance was still alive.

The Bullocks were dedicated to bringing up their young twins in the idyllic village of Picton, on the southwestern outskirts of Sydney.

With her father Darren by her side, Sienna is fighting for her life after being transported to the Westmead Children’s Hospital in Sydney in a critical condition with head and chest injuries.

Mr Bullock, is a former mining executive and his wife Julie was an occupational therapist working for NSW Health.

The couple, who have been together 14 years, led a happy family life growing vegetables and baking biscuits at home with their twins.

Julie Bullock (left) with husband Darren (centre) and twins Hudson and Sienna, 7, and other family members last year. Picture: FacebookSource:Supplied

Devoted couple Julie and Darren Bullock had been together more than 12 years before the tragic crash that killed Julie and the couple’s twin son Hudson. Picture: FacebookSource:Supplied

Hudson with his arm around twin sister Sienna told witnesses after the fatal accident that his sister was trapped in the wreckage, before he was taken to hospital where he died. Picture: FacebookSource:Supplied

Julie Bullock, with her seven-year-old twin son, Hudson, both of whom were killed in the fatal Hume Highway car crash on Monday as she drove her children to school. Picture: FacebookSource:Supplied

As a family, the Bullocks took trips to the museum, to play minigolf and on holidays overseas and to the snowfields.

Mr Bullock had weathered a public controversy over his mining job, but had come through the other side with the support of his close family unit.

On Monday, Mrs Bullock was driving Hudson and Sienna the 12km commute from the family home in Picton to Wollondilly Anglican College in the town of Bargo.

As Mrs Bullock’s Mazda four-wheel drive drove south down the Hume Highway, onlookers saw a Holden Astra travelling north veering across the median strip and hitting the Bullocks’ car.

Witnesses later said both vehicles were “totalled”, but Julie, Hudson and Sienna were all initially still alive — though trapped in the Mazda.

Drivers stopped to help the Bullock trapped in the overturned Mazda.

According to the Daily Telegraph, witnesses said a truck driver pulled off the dashboard to try and free Julie Bullock, while others cut the children out of the back of the vehicle.

Mrs Bullock then crawled out by herself and laid beside the car, while people gave her compressions until the ambulance arrived.

The wreckage of the Bullock family’s Mazda from which Julie and her twins had to be rescued, but tragically only Sienna survived. Picture: Ian SvegovicSource:News Corp Australia

The twins lived in the idyllic village of Picton on Sydney’s outskirts.Source:Supplied

Sienna and Hudson, 7, enjoyed a happy family life. Picture: FacebookSource:Supplied

Pictured with their dad, Darren Bullock, at Thredbo, the twins enjoyed family outings, holidays and a happy home life. Picture: FacebookSource:Supplied

Hudson told people helping his mother that it was his twin sister who had been trapped in the wreckage.

Hudson was taken to Liverpool Hospital in a critical condition, but died on Tuesday morning.

Sienna was taken to Westmead, where she remains in a critical condition.

“We were trying as hard as we could to keep the little boy alive and awake but he went unconscious on us. There was nothing we could do,” the witness told the Daily Telegraph.

“There was also a nurse who just happened to be driving by and she tried her hardest.

“The boy told us it was his twin sister. I’d like to go to the little boy’s funeral.”

The woman driving the Holden Astra was also taken to hospital with injuries.

Mr Bullock, the former district manager of the Picton Mine Subsidence Board, is believed to have spent the night at Westmead by Sienna’s side.

Police attend the scene of the tragic crash where Julie Bullock and her twin children were trapped in the car after another veered over the median strip head on into the Bullocks. Picture: Ian SvegovicSource:News Corp Australia

Julie Bullock was a loving wife and devoted mother of seven-year-old twins, Hudson and Sienna. Picture: FacebookSource:Supplied

Twins, Hudson and Sienna Bullock, enjoying dress-ups at a younger age. Picture: FacebookSource:Supplied

Before the fatal crash, the Bullock family had endured normal family hospital excursions — Darren for back surgery, Hudson for appendicitis and a bee sting.

Darren and Julie met in the early 2000s and married, with their twins born in May 2009.

When the children were babies, the Bullocks lived for a time in Singapore.

Sienna grew up loving art and animals, while “Huddy” was a typical little boy, loving cars and adventure.

Mr Bullock worked as the Southern Coalfields district manager before being appointed as the Picton manager of the Mine Subsidence Board.

It was a role which was to bring him into contention with the former NSW Independent Commission Against Corruption chief, Megan Latham.

Darren Bullock with his seven-year-old twins, Hudson and Sienna, on a museum visit. Picture: FacebookSource:Supplied

Hudson Bullock in hospital after contracting appendicitis. Picture: FacebookSource:Supplied

Last year Ms Latham — who has since resigned from the corruption watchdog following her controversial investigation of senior crown prosecutor Margaret Cunneen — found Mr Bullock had misappropriated $400,000 to spend on house extensions and a swimming pool.

Mr Bullock has always maintained his innocence of any of the ICAC claims.

Darren and Julie Bullock kept in regular contact with a large circle of family and friends, keeping them up to date with the twins’ progress.

The Bullocks took Sienna and Hudson on family holidays to Malaysia and Thredbo and enjoyed simple family life in Picton, where they raised a rescue dog.

In February 2014, Mrs Bullock posted on Facebook that she was celebrating a decade Darren as “friends, lovers and life partners”.

“The luv of my life spoilt me with flowers tonight,” Mrs Bullock wrote. “10 years and the love is still there. Luv romance xoxo”