Although police have said the attack is not believed to be gang-related, the woman says she doesn't want her name used because she and her family fear gang retaliation.
She says her brother, who is 47, had stopped to get coffee while waiting for a bus in the Cornwall Centre mall earlier this week.
That's when he and three other people were stabbed by a teenager wearing a red bandana.
The other three victims were quickly released after treatment but her brother's wounds were more severe and he is still in hospital recovering.
She says he told her he thought he had been hit from behind.
“He thought he was punched and he was going to chase the individual and he collapsed,” she told radio station CJME.
“What’s this world coming to? Canada is supposed to be one of the safest countries to live in and it’s getting to the point where people don’t even feel safe."
But she said despite his bad luck in being randomly targeted, good fortune shined on him in the form of a helpful passerby.
“Our brother was lucky, he was very lucky," she said. "There was a lady in the mall that if she didn’t apply pressure to his wound, he wouldn’t be with us."
She said she hopes the justice system will provide the type of punishment that will actually make the person responsible for the attack think twice.
“I sure hope the young individual that conducted this act really asks himself, does his life mean so little to him?”
A 15-year-old boy has been charged with aggravated assault and assault with a weapon.
Police say they still don't know what prompted the attack.