The Dec. 26, 2017, crash occurred on the New South Wales Coast near Sydney, Australia, and was allegedly caused by a "serial traffic offender" with more than 60 convictions on his record, according to Metro.
The machine was allegedly turned off just a day after her family's funeral, which saw her mum Vivian, dad Lars and sister Annabelle laid to rest.
Annabelle was transported to Liverpool Hospital, where she died three days later.
There has been no official confirmation from the NSW Police or hospital that the actress has died.
Annabelle tragically passed away as a result of her extensive injuries on December 29.
The 4WD driver, Ulladulla man Craig Anthony Whitall, 51, was also killed.
Jessica, 29, had her life support switched off on Thursday as devastated family members have kept a bedside vigil at St George Hospital in the hope that she could be brought out of her medically induced coma.
The remains of those killed in the crash were so badly burned, they had to be identified by their dental records, SBS reported.
Police believe the crash occurred when a large vehicle crossed the centre line and crashed head on with the Falkholt family's auto.
"The irony of this tragedy is that Lars was such a careful driver".
"Their lives ending on a highway makes absolutely no sense".
'Whenever asking how long it would take to drive somewhere I would suggest an average for a normal driver and then add some additional time for the Lars factor. We'd always have a laugh.
Ponticello also spoke about the love between his sister and brother in law, "They are together and always will be".
"Lars, Vivian and Annabelle will be deeply missed by Vivian's brother Paul Ponticello, his children Paul and Natalie, along with many relatives and friends both near and far", the notice read. Her first feature film, Harmony, is due for release later this year.