Wheelchair-bound Steven Hinrichsen, 63, died in a brutal and sustained attack in December 2018.

The stabbing was inflicted by Gavin Scott Skinner, 47, who was found guilty of murder.

Also present during the attack was Robert John Thrupp, 48, who was found guilty of the lesser charge of manslaughter.

The victim's wife, Tanya Hinrichsen, 44, was not present but was found guilty of murder on the basis that she encouraged Skinner to kill her husband.

Sentencing the trio in the Supreme Court on Friday, Justice Sophie David said the killing involved a "brutal and violent attack on a man who was partially incapacitated, confined to a wheelchair and sedated by some form of medication".

"Gavin Skinner, you inflicted a last humiliating assault on him by smashing a framed picture which had previously been on the wall of the bedroom he shared with Tanya Hinrichsen over his head," the judge said.

"This was nothing less than a frenzied attack."

Justice David told Hinrichsen that her conduct was an egregious abuse of her husband's trust.

"You were his wife and you were his carer. You knew that he loved and trusted you," she said.

"He was a vulnerable man, incapacitated and confined to a wheelchair, yet you encouraged another to murder him for your own selfish purposes.

"It is difficult to comprehend your motivation to commit this offence. It was open to you to simply leave your husband.

"There was simply no need to encourage another to murder him."

Justice David jailed Skinner for a minimum of 24 years, Hinrichsen for at least 22 years and Thrupp for at least seven years, two months and 13 days.

She said while Thrupp did not inflict any of the injuries suffered by the victim, he was present during the killing and was ready to lend support to Skinner.

Australian Associated Press