The grandmother of two young Alberta boys drowned by their mother two years ago sobbed as she described in court how much she misses them.

"I felt like my heart was ripped out," said Audrey McConnell in her victim impact statement at her daughter-in-law's sentencing hearing Wednesday.

"I would lay in bed with their little shirts in my hands, crying and just trying to remember their scent," she said.

"Nightmares of them lying in their coffin with their arms wrapped around each other goes over and over in my mind," she said. "They were so cold."

Curtis and Allyson McConnell shown with sons Connor and Jayden in an undated photo. (Facebook)

Allyson McConnell drowned Connor, 2, and 10-month-old Jayden in the bathtub of their Millet, Alta., home during a bitter divorce battle with her husband Curtis McConnell.

During the trial, the prosecution argued McConnell killed her boys out of revenge, but her lawyer argued McConnell's mind was so clouded by depression, booze and sleeping pills that she could not know what she was doing.

Justice Michelle Crighton agreed, convicting McConnell last month of manslaughter rather than the more serious charge of second-degree murder.

Today the boys' father and grandparents tried to put into words how the boys' deaths affect them.

"I love them with all my heart and miss them so much," said Audrey McConnell.

She also described how she places birthday candles on the boys' grave while singing Happy Birthday.

"Connor would have started kindergarten this fall," she said.

She told the court she looks forward to the trial ending so "we can mourn our precious babies in peace."

The boys' father, Curtis McConnell declined to read his statement out, while the prosecutor read the statement from the boys' grandfather.

In his written statement, Curtis McConnell said he has flashbacks of finding his sons dead in their home, and has a shakiness in his hands that "won't go away."

"To come home to find my kids left to rot by the person I love and trusted more than anyone else has made it so hard to trust anyone again," he wrote.

Crown prosecutor Gordon Hatch recommended a 12-year-sentence, arguing it's up to the court to reflect the horror the children must have felt.

He suggested Allyson McConnell should get 3 years' credit for time she has spent in psychiatric care at Alberta Hospital since the killings.

Lawyer Peter Royal argued McConnell should get double credit for her time served and be released.

"There are no winners here," he said, "no matter what sentence is imposed."

McConnell, who was served with notice of deportation a few days after her conviction, wants to return to her home country of Australia and has the support of the Australia High Commission, said Royal.

The judge has reserved her decision until June 4.

Manslaughter carries a penalty anywhere from probation to life in prison.