Falkholt had undergone several surgeries since the crash, according to the UK Telegraph.
Their parents, Lars and Vivian, were killed instantly.
"Home and Away" actress Jess Falkholt has had her life support switched off, after failing to recover from the Boxing Day auto crash that had already claimed the lives of her parents and sister.
The 29-year-old has been in a coma since the horror collision, which also claimed the life of the driver of the other auto involved, 50-year-old Craig Whitehall.
It has been revealed that the killer driver Craig Whitall had been declared an habitual traffic offender by the courts with more than 60 convictions to his name.
The Falkholt's family vehicle was hit by a four-wheel drive on Boxing Day, with the sisters pulled from the wreckage before it erupted in flames with the bodies of their parents inside.
Lars, Vivian, Annabelle and Jessica Falkholt. It's believed he was driving home from the methadone clinic with an investigation taking place on whether he was under the influence of drugs at the time of the crash.More news: James Damore sues Google for discrimination against conservative white men
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Her younger sister, 21-year-old Annabelle, passed away in hospital soon after.
At the Falkholts' funeral, loved ones paid tribute.
News.com.au report that Mr. Ponticello told the service: "The irony of the tragedy is that Lars was such a careful driver".
A family friend said, "They were a very close family and had been on a quiet getaway", according to The Telegraph as reported by Sydney Morning Herald.
"Whenever he'd ask to drive somewhere I'd suggest a time for an average driver and add on some additional time for the "Lars factor" because he was so careful". We always had a good laugh.
"We take a little comfort in knowing they will be together". "You will be deeply missed". She had just completed filming for the title role in "Harmony", scheduled for a 2018 theatrical release.