She was in her car, stopped at roadworks when a logging truck crashed into the rear of her Toyota Kluger. The impact pushed the car into three more vehicles - and sent five people to hospital.

The 33-year-old has been in an induced coma since the crash on the Barton Highway on April 13. Due to extensive spinal injuries, the single mother of three is expected to be left paraplegic.

Seated in the car were her two sons, aged 10 and 6, who miraculously escaped serious injury. Her five-year-old daughter was in day care.

Ms Allred was trapped for some time before Fire and Rescue NSW freed her. Now she's in Royal North Shore Hospital battling spinal injuries, broken ribs, a broken leg and a lung infection.

Her father, Karl Allred, said the situation was like a nightmare.

"It's a horrible thing she's going through, I wouldn't wish it on my worst enemy," he said.

Doctors tried to bring her into consciousness, but her broken ribs were too painful to breathe. So she remains in a coma, breathing with the assistance of a tube amid discussions about a possible tracheotomy.

On Monday, she flatlined due to medication issues but recovered and is slowly gaining strength.

"She's alive, she is critical but stable and everyday she's getting better and stronger," Mr Allred said.

"The signs are optimistic, years down the track she may be able to walk but no one knows. Right now the prognosis is she will be paraplegic with no bowel or bladder function.

"They've already told us that she's never gonna walk again, but never is a long time.

"The spinal cord wasn't severed or cut in any way, it was compressed by broken spine fragments."

Ms Allred is expected to remain at Royal North Shore Hospital for at least six months before moving to the Royal Prince Alfred Hospital to begin rehabilitation.

Friend Rebecca Alvarez said Ms Allred was fiercely independent and always helped others.

"She has a very strong personality - very independent, very strong willed - but also very caring and has an amazing sense of humour," Ms Alvarez said.

"She is the type of person that will go into fight for everyone else and help everyone else. She is not used to having people help her."

The Yass community, where Ms Alvarez lives, has rallied around the family. Neighbours are looking after the pet cat and blue tongue lizard. They are also mowing Ms Allred's lawn and keeping up with the gardening.

"We have a very strong family network and very strong friend networks. She won't go without and won't have to worry about anything," Mr Allred said.

The family has set up an online fundraiser to assist with costs.

The truck driver, a 59-year-old man, was charged with dangerous driving occasioning grievous bodily harm, drive manner dangerous, and negligent driving occasioning grievous bodily harm. The Victorian man was granted conditional bail to appear before Yass Local Court on June 17.