Canadian citizens returning to Canada who present other documents, such as a Certificate of Canadian Citizenship, birth certificate, provincial driver’s license, or foreign passport, instead of a Canadian passport, may face delays or be denied boarding by transport companies.
# persons holding a British National (Overseas) Passport issued by the Government of the United Kingdom to persons born, naturalized or registered in Hong Kong;
# persons holding a valid and subsisting Special Administrative Region passport issued by the Government of the Hong Kong Special Administrative Region of the People’s Republic of China;
If this person is just going to visit in Canada for short period and then going back to HK, it will be okay to use this 特區護照. If not, and he is coming in with a one-way ticket, be prepared to explain why to custom.