Annabelle died as a result of her injuries last Tuesday and yesterdayThe Daily Telegraph reported Falkholt's life support had been turned off.
Australian police are still investigating the crash, which also killed 50-year-old Craig Whittall, who was driving the other auto involved.
Home and Away star Jessica Falkholt has had her life support switched off and remains in a critical condition following the horrific vehicle accident that killed her parents Lars and Vivian Falkholt, and her sister Annabelle.
Jessica had been fighting for life after being involved in the same horrific auto crash on Boxing Day that killed her family.
According to police records, Whitall had used 28 different aliases over the years in his efforts to avoid the police due to his long list of driving offenses.
Annabelle's best friend Brittany Macchetta said the 21-year-old had a passion for travel, art and Harry Potter.
Last night, the Daily Telegraph revealed Jessica's extended family had chose to switch off her life support in the hope that she could be woken from her coma.
Falkholt has been clinging to life after the fiery head-on on the NSW south coast which claimed the lives of her parents Lars, 69, Vivian, 60, her sister Annabelle, 21, and Whitall.
She remains in a critical condition, a spokeswoman for St George Hospital told AAP on Friday. Her parents died on the scene of the crash while she and her sister were airlifted to the hospital. Jessica was sent to St George's Hospital, where she has undergone multiple surgeries including having part of her skull and her kidney removed.
"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".
Wednesday's service was held at St Mary's Catholic Church at Concord, in Sydney's west.
"(It's) a day that will be hard to erase from our memory".
Ponticello also spoke about the love between his sister and brother in law, "They are together and always will be".