The youth who assaulted staff members at the Selkirk Behavioural Health Foundation has received an adult sentence for the "stark horror" of the attack and because he is a danger to the public, a judge said on Thursday.

Provincial court Judge Dale Schille looked at Lionel Harper, 17, during sentencing at the Manitoba Youth Centre and told him "this case is one that stands apart in terms of level of violence."

The teenager looked down as he was handed the sentence of six years in a federal penitentiary for two counts of aggravated assault. He was given credit for 18 months of time served, leaving him with 4½ years to serve.

Harper was one of three people charged in connection with a brutal attack on two youth support workers at the addictions treatment centre, located in the small city about 35 kilometres north of Winnipeg, on May 29, 2016. The two others were both sentenced as youths, and their names can't be released due to provisions of the Youth Criminal Justice Act.

One of victims, Jackie Healey, was on the last day of her work placement at the centre through Red River College. The attack broke several bones in Healey's head and face, and she lost vision in her left eye.

Jackie Healey was hit with a baseball bat and a sock filled with pool balls during the attack. (Facebook)

Her parents and sister attended the sentencing, but it was too difficult for Healey to face her attacker, her family said.

"She wanted to come but it was too hard for her, and she didn't come to court due to the injuries that she had and everything else. Very hard on her," said her father, John Healey.

"But I think she will be pleased with the sentencing today."

'The devil in disguise'

Healey's victim impact statement was read in the courtroom, detailing the continuing pain she suffers from the assault, in which she was hit with a baseball bat and a sock filled with pool balls.

She spoke about how devastating it was to lose sight in her left eye, making vision in her right eye worse, and how she now sees everything differently.

"When I would see my family, they would not look the same," Healey said in the statement.

She said she went into the addictions centre to help people but instead she found "the devil in disguise."

"Harper ruined my future in this line of work," she said, adding that while she tried, it's too difficult to continue in the field.

The emotional trauma also left Healey crying in bed for nearly a year, she said, and she started distancing herself from family and friends. She also turned to drinking and drugs to cope with anxiety and depression following the attack.

'System on a whole that failed'

Harper, who wore a grey shirt and sat in a chair inside a clear enclosure, looked up while the victim impact statement was read. But he did not submit any of his own comments or an apology when given the opportunity by the judge.

Instead, the defence lawyer told the court Harper had accepted responsibility for his actions.

"He knows there are no words he can say or articulate [to show] the level of remorse he has," the defence lawyer said.

Court also heard how Harper grew up without parents around and was failed by the child welfare system time and time again. The defence lawyer also explained that Harper should never have been at the behavioural centre, and was supposed to be placed somewhere else.

"Why was he even there?" She asked. "This is a system on a whole that failed [Harper]."

The defence said Harper improved his behaviour over the last year, but last summer he did attack another youth detained at the centre in an unprovoked assault.

The judge pointed to Harper's cognitive deficits and traumatic background, but said he was the main player in the attack that left two people with physical and psychological scars.

"He can never make whole the victims in this matter," Schille said.

Schille told Harper the sentence is needed to "protect the public and separate you from the community," given his background and capacity for violence,

John and Mary Healey stood outside the Manitoba Youth Centre on Thursday. They say the adult sentence has brought some closure. (Kelly Malone/CBC)

Following the sentencing, Healey's family gathered outside the youth centre, saying they felt a sense of relief that the court process was over.

But they said they were disappointed that there had not been any support from Red River College throughout the process.

"With Red River College there [was] no support for Jackie there; they never came to any of the courts. No support," John Healey said.

"They even actually kicked her out of school. There was no support in school … It's a shame."

Healey has filed a lawsuit against Red River College and the Selkirk Behavioural Health Foundation, claiming both acted negligently by leaving her alone with dangerous offenders. The allegations have not yet been tested in court.

"To show support to Jackie, to be there for her, somebody to show up at the courts … would have made a big difference," John Healey said.

Her family said that Healey was struggling to leave her house, and sometimes spends weeks without going outside.

They hope, with time, she can once again be the bubbly and resilient young woman she was before the attack, John Healey said.

"Hopefully things will get better for Jackie," he said.