Initially, you might only have to complain to the manager or owner
of the residence for the matter to be investigated and dealt with.
If that doesn't help, you may have to look at other options.
Some provinces have laws that require anyone to report any suspected
abuse of adults living in institutions and seniors' lodges to specified
authorities. Other provinces have laws that allow for reporting
of suspected abuse, but do not make it compulsory. In both cases,
there is normally also a statement in the law that no action can
be taken against the person who made the complaint.
Even if a province does not have a law that provides for reporting
suspected abuse of seniors in an institution, there are other ways
to initiate a complaint. It is always possible to go to the police
if you suspect that someone is being harmed or mistreated. Also,
there will likely be some kind of licensing body in the province
with regard to operating seniors' residences, together with detailed
rules about how the residences must be operated. You might consider
making a complaint to the licensing body.