STORY: Bonnie, who had four sons and was fostering two other children, was killed in front of her home as she tried to protect her family - all six young people were in the house, Arcand said.
"She's not a victim. She's a hero," he said.
Arcand described his nephew as "a great kid" who helped his family and worked in the community to build homes.
Canadian police searched into a fourth day on Wednesday for the remaining suspect in the stabbing spree.
The fugitive, Myles Sanderson, and his brother, Damien Sanderson, are suspected of stabbing 10 people to death and wounding 18 on the James Smith Cree reserve and nearby village of Weldon on Sunday. Damien Sanderson was himself found killed a day after the attacks.