Kalila Grevell, a family member, has set up the page (gofundme.com/maria-sfamily) to assist the family, from Canberra, with funeral costs.

The female passenger, Maria, travelling in the car died at the scene shortly after the accident, while the male driver, Ben, and four-month old baby Reuben were taken to hospital in Canberra.

The Barton Highway remained closed for a number of hours, with a series of traffic diversions in place.

On July 24, Ms Grevell said her step brother was still in intensive care unit.

“His life has been turned upside down in the blink of an eye. His son left without his mother. It will be a long road to recovery. Emotionally and physically, I doubt it has even hit home yet,” Ms Grevell writes on the page.

Emergency services were called to the accident near the Yass Valley interchange at Manton about 3.50pm, where the car had left the road and hit a tree.

Ms Grevell, on behalf of the family, has thanked all involved during the accident.

“Thank you to all the emergency personnel and civilians who were on scene that had to be a part of such a horrific ordeal,” she told the Tribune.

Ms Grevell has also reassured everyone that the baby involved is uninjured and is being cared for. She said the safety aspect of the rear-facing restraints played a role.

“So many people don’t realise it. I’d hate to think what would have happened had he been forward facing. Legally, you can turn them around at six months but this may not be best practice,” she said.

“Thank you to the Yass community and wider Canberra area for their support and generosity,” she said.

Those who attended the scene may seek help from the following services: