Mr May, a former mayor of Hepburn Shire, died a week after he was involved in a car accident in May 2017, with Stuart Paul Usherwood, 34, pleading guilty to dangerous driving causing death.

His eldest daughter, Stephanie, revealed she found out she was pregnant the same day she turned off Mr May's life support.

"Dad loved his life, and now I cry for my loss and my 15-month-old boy who will never meet him," she said in court, reading from her victim impact statement.

"I think about his eagerness to meet his grandchild and be there for his milestones.

"His well-worn leather jacket has pride of place in the living room.

"Mum's death was blameless, but Dad's wasn't."

She added her relationships had become strained, and she had become more aware of other drivers on the road.

"Since the crime, it's highlighted my level of suspicion about the competency of other drivers," she said.

The deceased's younger daughter, Carla, also read out her victim impact statement in court, noting their mother died in a tsunami in 2009.

"Losing Mum felt like a large part of my world had gone - Dad was an incredible presence in my life after Mum died," she said.

"They said we could see him (after the accident in hospital) and it was one of the most difficult things to witness - his expressionless face with no sign of movement.

"This was our strong, resilient Dad.

"We were taken to a windowless room and told it was most likely he was brain dead, that he'd never be the same again even if he did wake up, which was unlikely.

"Turning off his life support is one of the hardest things I've ever had to do."

The sisters noted the financial strain on the family, particularly managing Mr May's organic farm.

The court was told Usherwood was driving on the Daylesford-Ballarat Road near Gong Gong on May 21, 2017, and had pulled over to check his GPS.

He then pulled back onto the road, just as Mr May approached on his motorbike.

Mr May struck the side of Usherwood's SUV, and received critical injuries.

There was a dispute regarding whether Usherwood had used his right indicator before pulling back onto the road - in the police interview, he said he had, but police photos from the scene show only the left indicator activated.

It was also noted there were no signs that Mr May had braked as he approached, and Usherwood had seen a headlight in his rear vision mirror before he attempted to perform the U-turn.

The lawyer for the defence, Ray Alexander, said Usherwood's daughter had been born the week of the accident, and had returned home from the hospital the day before.

Usherwood, who was disqualified from driving, had driven from Halls Gap to Ballarat to retrieve a bassinet for his daughter, and was driving to Gong Gong to pick up a breast pump his wife had bought on Gumtree as his mother-in-law and friend were unavailable.

The court was told traces of methamphetamine and amphetamine were detected in Usherwood's blood after the accident, which Mr Alexander said was due to taking an unknown stimulant pill Usherwood believed was caffeine.

It was admitted Usherwood had a history of drug use, but had not used any for several years.

Mr Alexander spoke about Usherwood's early life and the issues with his two young children, who have severe issues with autism, and the difficult circumstances with the birth of his third child.

He also read out a letter from Usherwood, where he apologised to the May family.

"I'm aware they'll always think of me as a monster, and it breaks my heart, it's so far removed from who I really am," he wrote.

"It's only to a degree that I can understand how they feel.

"I've known since the day I was charged I would face jail time - I do embrace it.

"I'm intensely repulsed by the notion I'm presenting myself as the victim - this has changed every aspect of my life, and I will carry this forever.

"I will think of Mr May every day of my life.

"On my daughter's birthday, at Christmas, on Father's Day - I think of his daughters and the cards they won't be able to give him."

Judge Howard Mason will proceed to sentencing later this month.

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