McMaster Children's Hospital is challenging a First Nations mother's decision to withdraw her daughter from chemotherapy. (McMaster)

An Ontario court on Wednesday heard final arguments in the precedent-setting case of whether a child can be forced into protective care without the say-so of the Children's Aid Service. 

The Ontario Court of Justice in Brampton, Ont. is considering the case of a young First Nations girl with acute lymphoblastic leukemia, whose mother in August called off her chemotherapy in favour of a U.S. clinic that she says is more in line with their traditional indigenous culture.

When Brant Children's Aid Society did not to intervene, McMaster Children's Hospital in nearby Hamilton, Ont., where the girl had been receiving chemotherapy, took the unusual step of going to court, to force the agency to intervene and return her to treatment. 

The McMaster medical team has stated the girl has an 90 to 95 per cent chance of survival on chemotherapy but, without it, the cancer could kill her.

A lawyer for the Six Nations band said in court last week that forcing the child back into chemo treatment would be the same as sending the child to a residential school to face abuse.

'This mother is doing everything possible to protect her child. She’s just doing things that doctors disagree with.' - Mark Handelman, Brant Children’s Services lawyer

Mark Handelman, the lawyer for Brantford Children’s Aid Services, also argued the case is "a treatment dispute, in our view, not a child in need of protection.”   

“My god — this mother is doing everything possible to protect her child. She’s just doing things that doctors disagree with,” Handelman said in court.

The mother, who, along with her daughter, cannot be identified because of a publication ban, told CBC News the family had a comprehensive health-care plan.

“We would not make a choice that would compromise her health or life. There is enough case evidence behind Onkwehonwe medicine and the practices at [the Hippocrates Health Institute​] that we know we have made the right choice," she said. Her daughter has since been treated at and returned from the U.S. clinic 

"My daughter feels great. I truly believe that there will be a positive outcome and this will be ended soon," her mother said. 

Judge Gethin Edward, presiding in this case, expressed concern about the legal precedent he could be setting, about who gets the final say over children in the future — and one very sick child, right now.

Edward will read his decision Nov. 14.

With files from CBC's James Murray and Connie Walker