"Minor children who are less than 17 years of age and come to Canada to study without a parent or legal guardian must be cared for by a responsible adult in Canada. This person is known as a custodian. A notarized custodianship declaration, such as the form Custodianship Declaration - Custodian for Minors Studying in Canada (IMM 5646) (PDF, 1 MB), must be completed by the parents or legal guardians in the country of origin and by the custodian in Canada.
Minor children between 17 years of age and the age of majority in the province or territory (18 or 19 years old) where they intend to study, may need a custodian at the discretion of an immigration officer."1
It is the responsibility of the student's family to satisfy this requirement. Western University is not able to serve as a custodian.
See CIC's information on Minor children studying in Canada.