Family spokesman Taj Mohammed said the boy, Zain Hasan, is expected to be discharged from an Edmonton hospital later this month.
"It is good news," said Mohammed, the principal of Fort McMurray Islamic School where Zain attends kindergarten.
"He is off of the ventilator. He is in the recover section of the hospital and he will be two to three weeks before he is discharged."
Funerals for Zain's two-year-old brother, Zia, and eight-month-old sister, Zara, were held in Edmonton last week.
Mohammed said Wednesday that it is too soon to know whether Zain suffered any permanent injuries.
Aluminum phosphide can emit phosphine gas, which can cause long-term damage to a body's liver, heart and kidneys.
The family had recently brought a type of aluminum phosphide back from a trip to Pakistan to kill bedbugs in their apartment in Fort McMurray.
Two other children, aged four and seven, were released from a hospital in Fort McMurray last month.
The father, Syed Habib and the mother, Nida Habib, remain in Edmonton.
It is not clear how the family managed to bring the pesticide into Canada.
The Canada Border Services Agency and RCMP have said they are investigating.
Health Canada issued a warning Friday about what it calls the "extreme danger'' of using unregistered pesticides to fight bedbugs.
The Centres for Disease Control in the U.S. says phosphine is a colourless, heavier-than-air gas that can quickly spread and collect in hazardous concentrations in poorly ventilated or confined areas.
A Quebec coroner has concluded that two sisters found dead in their hotel room in Thailand in 2012 were probably poisoned by phosphine.
Coroner Renee Roussel said Monday that it is officially forbidden to use the pesticide to fumigate hotel rooms in Thailand, but that it might in fact still be used.