It all depends. I never said that we wanted our parents to stay here to look after our kid when we renewed their visa --- and we got the visa renewed successfully. Our reason was "to visit more cities and beautiful scenic spots in Canada during the best season here", or "to spend more time with my daughter and son-in-law during the Christmas season......". Yet we do have friends who have also successfully renewed their parents' visa with the reason that they wanted their parents to help them babysit their newborn. The typical saying is what? "Every case is different!"
Good luck!