Grandfather, 60, dies days after wife after they were struck by out-of-control car in Melbourne

A family tragedy has deepened with the grandfather who was hit by an out-of-control car in Melbourne dying in hospital.

The 60-year old was struck alongside his wife, who died at the scene, and their two-year-old grandson, who has now been reunited with the heroic woman who shielded him from the trauma.

The 91-year-old driver still has not been interviewed three days on from the crash.

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Tracey Jean will never be able to forget the trauma that unfolded outside her parents' doorstep.

"It was horrific," she says.

"The mum has told me that 'dad is now with mum'.

"She was texting me yesterday and she was in the hospital saying goodbye to dad."

The couple was walking along a road in Wantirna South in the city's east on Thursday with their grandson when they were hit by the out-of-control Yaris before it careered another 200 metres into a playground fence and park bench.  

The 59-year-old grandmother died at the scene while her husband and their grandchild were rushed to hospital.

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Jean cradled the little boy, comforted him and shielded him from seeing his grandparents.

This afternoon she was reunited with the boy.

The toddler escaped serious injury and is now home with his grieving parents.

Police are still trying to work out what caused the driver to lose control of her car.

In the minutes after the crash she was conscious and able to walk to a nearby home for help.

She remains in hospital and is yet to be interviewed.

The government is now revisiting Victoria's rules for elderly drivers.

Unlike other states, there is no requirement for medical assessments or tests beyond a certain age.