A DOMINEERING and neglectful father who stubbornly refused to make a single phone call that would have saved his diabetic daughter's life has been jailed.

But Richard Edward's co-accused - his "weak and cowardly" former wife, Debra - was spared immediate imprisonment for her role in the 2009 death of their 14-year-old daughter, Dawn.

This morning, the Supreme Court jailed Richard for 4 ½ years, with a non-parole period of three years and seven months.

Justice Kevin Nicholson said Richard was more criminally culpable than his ex-wife for their "abject failure" as parents of a sick child who weighed just 28kg when she died.

"It was plainly evident, and must have been to both of you, that Dawn was - and, for many days prior to her death, had been - extremely sick and obviously in need of urgent medical intervention," he said.

"Your crime was a stubborn failure, during that last week, to take heed of those obvious signs and take the simple step of obtaining medical assistance.

"Had a phone call been made and medical assistance obtained, Dawn would not have died ... Dawn's death should never have happened."

Richard, 49, and Debra, 52, pleaded guilty to one count each of causing the death of their daughter Dawn, 14, by criminal neglect.

Dawn, who was a triplet and one of the couple's five children, died in her family's Hackham West home on August 9, 2009.

Her death was the subject of a long-running police investigation, and the Edwards were charged - originally with manslaughter - in January last year.

During sentencing submissions, prosecutors told the court Dawn had died of hyperglycaemia, or high blood glucose levels, and dehydration.

They said Dawn had Type One diabetes and was insulin dependent - her parents, meanwhile, had failed to obtain medical attention for her when she was "obviously sick".

Prosecutors said Richard and Dawn had failed to make a single phone call to doctors in the week before Dawn died - a call that would likely have saved her life.

They said the parents were well aware of the dangers of Dawn's condition, having previously taken her to hospital following a "seizure-like" incident.

Lawyers for Richard Edward said their client had wrongly "written off" Dawn's poor health as gastroenteritis and deeply regretted "failing" his daughter.

They claimed he had not called a doctor out of deference to his "house proud" wife.

Debra Edward's lawyers, meanwhile, said their client had an IQ of between 60 and 61 - putting her in the bottom 0.5 per cent of the population - as well as health concerns.

In sentencing today, Justice Nicholson said it was "a struggle" to understand how Dawn's death could come to pass.

He said the answer lay in the complex circumstances created by two intellectually-disabled parents raising five children, each with disabilities of their own.

Justice Nicholson said Families SA had received 26 notices about the Edward family between 1994 and 2009, indicating the children had poor hygiene and personal health.

He said Richard Edward refused every attempt the government department made to assist them.

"You were a controlling, dominant influence (and) neglected all your children with respect to the obtaining of medical and dental treatment," he said.

"Debra, you spent your days in your bedroom watching television (and) seem to have given up, long ago, any sense of being a parent.

"You admit being too weak and cowardly to go against (Richard's) wishes for the sake of the children's needs ... even when he was at work.

"You bowed to that pressure and, as a result, Dawn died in circumstances where you could have prevented it."

Justice Nicholson said Richard's crime was too serious to warrant a suspended sentence.

He suspended Debra's three-year, four-month term on condition of a three-year, $500 good behaviour bond - and warned her to strictly obey it.

"I will, Your Honour, I will do everything I'm told," she replied.

In a separate neglect case last month, SA teacher and principal Angela Puhle received a suspended sentence over the death of her severely disabled 27-year-old daughter Kyla, who was bedridden and weighed just 12kg when she died.

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