A man has pleaded guilty to criminal negligence causing death after his injured 89-year-old mother was left to die on the floor of their shared Winnipeg home.

Ron Siwicki was originally charged with manslaughter in January 2015. The Winnipeg guitarist, then 62, let his injured, elderly mother die in their Garden City home in November 2014.

On Monday, he pleaded guilty to criminal negligence causing death.

Siwicki wore a black suit and looked forward toward Court of Queen's Bench Justice Colleen Suche on Monday morning as Crown prosecutor Alanna Littman told court about how Siwicki left his mother, Elizabeth Siwicki, lying on the floor beside her bed for weeks before her death.

Left lying beside bed

Siwicki, a well-known guitar player in Winnipeg, lived with his mother in a home on Arrowwood Drive North.

He was the sole caregiver for his mother, who lived with dementia but received little followup treatment while under Siwicki's care, court heard Monday. She hadn't had prescriptions filled for nine months or seen a doctor for two years before her death, Littman said.

Siwicki became the lone beneficiary of his mother's estate after her husband and daughter died.

Elizabeth Siwicki fell out of her bed in November 2014, court was told. Ron Siwicki initially tried to help her up but when he couldn't move her, he left her lying on the ground.

Ron Siwicki's elderly mother died on the floor of their Garden City home in Winnipeg. (Sam Karney/CBC)

She stayed on the floor beside the bed for weeks until she died, court heard.

Between the time she fell and the time she died, Siwicki gave his mother a meal-replacement product called Boost, court was told.

He also left her on the floor when he went out to work playing music around the city.

The carpet where she lay became covered with feces and urine, and Siwicki's mother developed bed sores that, paired with not being moved from where she fell, caused her death.

Covered in dry feces

When Siwicki found his mother had died, he tried to clean her body before he called police. But when officers arrived at the home in 2014, Elizabeth Siwicki's hair was matted and her body was still covered with dried feces, court heard Monday.

​Siwicki was granted power of attorney over his mother in 2009, and a copy of that document was laid out on a table when police arrived.

Littman said the woman's injuries could have healed in a week or longer and wouldn't have led to death.

"He [Siwicki] was obliged to seek help for her and failed to do so," Littman said, adding the maximum penalty for such a case is life behind bars.

Michael Cook, Siwicki's lawyer, said his client was only doing what his mother had requested.

"His mom had said to him, 'Ronnie, I don't want to go to the hospital. Keep me at home. Take care of me at home.' And Ronald lived with his mom his entire lifetime," Cook said outside courthouse on Monday.

Although his client "should have called for professional help," Cook said Siwicki was still very attentive to his mother.

Dying with Dignity

The case highlights the importance of clearly spelling out what your loved one wants at the end of their life while they are still in good health, said Shanaaz Gokool, CEO of Dying with Dignity Canada.

"The single most important thing a person can do when they're putting together their advanced care plan, their living will, is appointing someone to make decisions, health-care decisions on their behalf when they're no longer able to," said Gokool.

"There are a lot of scenarios you can run through with your loved one," said Gokool.

"You may have discussions around wanting CPR, do not resuscitate, no heroic measure, understanding in what circumstances would a person just want comfort care."

Dying with Dignity offers advance care planning kits on its website to help make the conversation easier, she added.

Siwicki has changed: lawyer

Siwicki has changed a lot since his mother died, Cook said. He has moved out of the home they shared and lives in his own apartment. He's physically and mentally healthier and has received a lot of support from friends in the community, Cook said.

A few people sat in the court room to support Siwicki on Monday and Cook said he expects up to 70 people will be there for sentencing on June 26.

"He's very, very anxious right now, but he knows it's just months away now, not years away, and I think he feels comforted by that," Cook said.