SYDNEY, N.S. - The mother of a Canadian soldier convicted of fatally shooting a fellow reservist in Afghanistan broke down and cried Friday as she tried to apologize in court to the parents who lost their young son more than two years ago.

Ann Wilcox was testifying at the court martial of her son, 24-year-old Cpl. Matthew Wilcox, who was convicted in July of negligent performance of duty and criminal negligence causing the death of Cpl. Kevin Megeney of Stellarton, N.S.

A charge of manslaughter was stayed, but the soldier from Glace Bay, N.S., still faces a maximum sentence of life in prison.

The military judge hearing the case, Cmdr. Peter Lamont, said he would hand down a sentence on Sept. 29 at the Victoria Park garrison in Sydney.

At the conclusion of Ann Wilcox's testimony, in which she described how her son is now a "broken" man, the woman reached out the Megeney family.

"We just wanted them to know ..." she said, gasping for breath as she stifled a deep sob with a clutched tissue, "how sorry we are."

The emergency room nurse told the military court that her son was an energetic, outgoing and respectful young man who was deeply involved in his community.

But that was before his deployment to Afghanistan.

Since the accidental shooting on March 6, 2007, she said her son has become withdrawn, rarely sleeps, has violent nightmares and could be prone to suicidal thoughts.

"He's broken," she said. "He's not the same person. ... No matter what we try to do, we can't fix it."

She said her son has yet to talk to the family about what happened at Kandahar Airfield.

"No matter what time you knock on his door, he's awake," she said, adding that the young man is never left alone in the house for fear he might harm himself.

She also testified that her son's younger sister, Jennifer, refuses to stay at home alone with her brother because she's afraid she won't be able to help him through one of his nightmares.

The court has heard evidence that Matthew Wilcox and Megeney -- members of the Nova Scotia Highlanders who helped guard the main gate at the NATO base -- were playing a game of quick-draw in their tent when Wilcox's weapon went off.

A round from Wilcox's 9-millimetre Browning pistol struck the 25-year-old in the chest. He was declared dead in a nearby medical tent about 30 minutes later.

In earlier testimony, Matthew Wilcox said he fired in self-defence, believing his life was in danger because he heard someone behind him cock the hammer on a gun.

Matthew Wilcox's father Keith testified that the family is still on a "roller-coaster of emotion," having failed to find a way to help their troubled son.

He said he can't imagine what the Megeney family is going through.

As for his own family, the volunteer firefighter described it as being in a state of suspended animation.

"We really don't know how to deal with it," he said in a sombre monotone. "I don't know how to describe what we are experiencing."

One of the prosecutors in the case, Maj. Jason Samson told the court the infantryman should be sentenced to six years in prison, nine months of which should be served at the Canadian Forces Service Prison in Edmonton

As well, he said Wilcox should be reduced in rank to private and dismissed from the military.

"This is the least punishment necessary to maintain discipline in the Canadian Forces," Samson told Lamont.

He said a stiff sentence "will send a clear message to those soldiers contemplating unsafe weapons handling."

One of Wilcox's lawyer's, Lt.-Col. Troy Sweet, told the judge that Wilcox should be demoted, but not be kicked out of the military, and he should serve no more than one year at the military prison.

Sweet said Wilcox is a first-time offender with the full support of his commanding officers of his unit.

Wilcox's crime was "more akin to a short lapse in judgment," he said. "He has something to contribute to military life."

Samson conceded there were some mitigating factors, including the fact Wilcox showed some remorse on the night his close friend was killed.

As well, three senior officers testified Friday that Wilcox was a good soldier who was considered in the top third of the 30 to 40 corporals in Delta Company

But Samson said there were aggravating factors to consider.

He said Wilcox did not show any remorse during the trial, offering the excuse of self-defence rather than admitting responsibility.

As well, he was in a leadership position as a corporal, having had extensive training and four months of service in Afghanistan.

"It placed him in a position to know better," Samson said, adding that the judge should, at the very least, impose the minimum sentence for criminal negligence causing death as prescribed by the civilian Criminal Code, which is four years.

Under the National Defence Act, there is no minimum sentence for criminal negligence causing death if the crime is committed outside Canada, a legislative anomaly with a murky history.

When Lamont asked whether Samson believed Wilcox acted in self-defence or had been playing a dangerous game, the lawyer said it didn't matter because the punishment should be the same for such negligent behaviour.

"What he says he did was equally serious," he said.