Harper was found by a passer-by Saturday morning on a walkway by the Assiniboine River. She had been sexually assaulted the night before. Police said she had also been in the frigid water at some point and was suffering from hypothermia.
Holly Harper, an aunt who lives in Nestor Falls, Ont., said Tuesday the teen will pull through.
"Rinelle is fighting," she said. "She's getting stronger. She has a lot of support around her, a lot of love and support. And there's people praying for her."
Grand Chief David Harper of Manitoba KeewatinowiOkimakanak, an organization that represents First Nations in the province's north, is a distant relative of Rinelle and visited her in hospital Tuesday.
"What she went through, it's totally unacceptable, nobody should be going through that, especially at the age of 16," he said.
Rinelle, whose family is from northern Manitoba, had been staying in a dormitory at Southeast Collegiate, where she goes to high school.
CBC has been told the teen went out with three male friends on Friday night.
Wade Keeper, another friend, spoke with one of the three after he heard about the attack on the girl.
Keeper said the friend told him the three left the girl at one point.
"He told me that he was going go to a store and buy some whatever and the three of them just went, just took off, and he said that's all he knows."
Keeper said the friend was really upset when he heard what had happened to Rinelle the next day.
"It's pretty much everybody went their separate ways," he said. "I don't know why Rinelle didn't go back to the lodge."
David Harper said the teen now needs time to recover.
"Looking at her, how could somebody treat another person like that, where their life is meaningless?"
A rally in downtown Winnipeg, at the corner of Portage Avenue and Main Street, was being organized by family and friends of missing and murdered indigenous women. It was to take place Wednesday at 4:30 p.m. CT.
David Harper told CBC earlier that Rinelle Harper's family supported the rally and would provide a spokesperson
to talk to media beforehand.
But late Tuesday, leaders in the aboriginal community tweeted that the family was opposed to the event.
CBC has not be able to reach the family for clarification.