Now 33, the injuries sustained on that day in 2017 have left him unable to communicate properly or walk, and have him reliant on permanent care.

His then girlfriend Jenna Dodds, who was driving the Mazda at the time, appeared in the County Court this week to plead guilty to dangerous driving causing serious injury and conduct endangering persons.

She collided with the side of a Ford on the Hume Freeway on May 12, 2017 at Wangaratta South, before it veered off the road and hit a tree.

Both Dodds and her boyfriend in the passenger seat were airlifted to hospital.

The woman in the other car suffered only minor injuries.

The man was in a coma and needed a brain operation, spending the next 15 months in hospital or recovery making slow progress, until he moved to Albury for assisted care.

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His mother submitted a victim impact statement to the court on his behalf, relaying his feelings of "loss, frustration, anger, depression and inadequacy".

The crash had occurred on Mother's Day and she recalled the "heart-wrenching" feeling of not knowing if her son would survive.

"I sat in the police station the next day and listened to the severity of the crash and could not fathom what was really happening," she said in her victim impact statement.

Prosecutor Jessica Fallar said Dodds, now 30, of Benalla, had no criminal history or prior traffic offences.

"The brain injury and the impact of that is lasting, it's permanent, and it is a tragic circumstance that has come about. He will no longer come back to how he was before," she said.

"A term of imprisonment is warranted, however taking into account her prior good character and the relative brief nature of the offending, then a combination of imprisonment and CCO is within range."

Dodds' barrister Charles Morgan said his client had expressed her feeling of guilt to medical professionals and others since the crash.

"She understands the impact that this event has had on others," he said.

Dodds has mostly recovered from the injuries she sustained in the crash, which included back pain and problems with her ribs, but the psychological pain continued.

She struggled to remember the crash at the time.

"Ms Dodds accepts that jail is a reality for her in the near future and she accepts the impact that will have," Mr Morgan said.

Judge Martine Marich will hand down her sentence on October 30.

"In relation to COVID, moving your client from what is a moderate to low-risk environment (in Benalla) to the high-risk environment of metropolitan Melbourne for her to serve time ... that appears to me to justify a combination sentence (of jail and community work)," she said.