ETAs are genuinely easy to obtain and are not processed manually so unless the applicant has a criminal record or has been removed from Canada they should get an ETA very quickly. Like any other visitor they will be assessed at the border for proof they are a genuine visitor, they have the funds to support their visit, they have strong ties to their own country, etc. Previous international travel history especially to certain countries also helps. The majority of the family members of protected people or refugees need TRVs to enter Canada. The chances of approval are also very dependent on their personal profiles. How long it has been since their family member claimed asylum or came to Canada as refugees has an impact on TRV approvals as do the conditions in their home country and whether there have been changes since their family member claimed asylum or became a refugee. All that family members can do is submit the strongest application possible that has proof of why they will return home and that they are genuine visitors.