Can one apply for the parents/grandparents supervisa from -
Canada's parent and grandparent super visa is a temporary resident visa (visitor visa) which allows visitors to stay up to two years on each entry.
Canada requires applicants for visitor visas to apply outside Canada, either in their home country, or from a country which they have been admitted for a period of at least one year.
For all other applications [other than permanent residence] you must select the visa office that serves your country of nationality or the country where you have been legally admitted for at least one year.
The only exception allowing an application from within Canada is if the applicant has entered Canada on a student or work permit. (But it seems unlikely that such a person would need or qualify for a parent and grandparent super visa.)