Khayla Ann Reno, 29, sustained severe head injuries when the car she was driving and a semi-trailer collided at a notoriously dangerous intersection in the Riverina town on May 16.

The woman was airlifted to Canberra Hospital after the crash. Her daughters Eryka, 10, and Violet, 4, were with her in the car at the time and were taken to Westmead Hospital in Sydney.

Eryka subsequently died at the hospital and Violet remained in critical care there as of Thursday.

In a statement on Thursday, Ms Reno's family members said they were struggling to cope with the unbearable tragedy.

"The family would have done anything to save Khayla, Eryka, and Khayla's unborn baby, however this was just not medically possible," the family said in the statement.

"We have also been praying for and focusing on the recovery of Khayla's four-year-old daughter Violet."

Ms Reno was 19 weeks' pregnant at the time of the crash.

An ACT Supreme Court judgment published on Thursday said a foetus was generally considered "viable" from about 23 weeks.

The father of Ms Reno's unborn child, Jamie Damian Millard, launched legal action against the hospital last week.

Hospital staff told Mr Millard last Thursday that Ms Reno's condition had progressed to brain death and her unborn child wouldn't survive.

The Supreme Court judgment said when Mr Millard asked whether an obstetrician could assess Ms Reno, he was told no obstetrician would be called.

The judgment said the hospital proposed an initial "deadline" of 4pm on May 21 to turn off Ms Reno's life support, but extended the deadline until 6am the next day.

Mr Millard was granted an injunction to stop the hospital from turning off Ms Reno's life support on May 22.

On May 24, an independent report ultimately confirmed Ms Reno was brain dead, meaning the court no longer had any jurisdiction over her or her unborn child.

In the ACT, an unborn foetus is considered part of its mother - not an independent being - until it is born.

Mr Millard's Supreme Court matters were ultimately dismissed, but he successfully argued that Ms Reno's organs should not be donated.

Her family said they were disappointed Ms Reno was not able to donate her organs, but "took strength" in the six lives her daughter Eryka had saved through her organ donation.

Ms Reno's life support was turned off on Thursday.

In a statement released to the media on Thursday morning, Mr Millard said the hospital had "rubbished" him.