There are multiple news agencies published the following statement from government web page,
What is not discretionary, it says, is for people to spend the pandemic period with their Canadian family member to ensure each other’s health, safety and well-being. “It would be
beneficial to all parties, as the reunification of family members is a key point of the Order in Council,” it notes. “This allows for families to be together during this difficult time.”
https://www.thestar.com/news/canada/2020/05/03/canadians-with-foreign-national-spouses-face-obstacles-at-border.html
This is not an exhaustive list. Foreigners are also allowed to spend the pandemic period with their immediate Canadian family members to help ensure each other’s health, safety, and well-being. This allows families to be together during this difficult time, the government webpage says.
https://www.cicnews.com/2020/05/canada-refines-definition-of-essential-travel-during-coronavirus-0514270.html#gs.6k2dqv
for foreign national immediate family member(s) to spend the pandemic period with their Canadian citizen family member so they can help to ensure each other’s health, safety and well-being (This section is specifically to allow for the reunification of family members where it would be beneficial to all parties. This allows for families to be together during this difficult time
https://www.nextgenimmigration.com/blog/travel-non-optional-or-non-descretionary-reasons-covid19
Also, the "Orders In Councils" clearly states the followings,
Prohibition
2 Any
foreign national, as defined in subsection 2(1) of the
Immigration and Refugee Protection Act, is prohibited from entering Canada if they arrive from a foreign country other than the United States.
Non-application
3 (1) Section 2 does not apply to
(a) an immediate family member of a Canadian citizen or of a
permanent resident as defined in subsection 2(1) of the
Immigration and Refugee Protection Act;
https://orders-in-council.canada.ca/attachment.php?attach=38990&lang=en