A: No. The landlord has rented out the rental premises to the tenant(s). Your mother is obviously a guest. The Act prohibits the landlord from restricting who the tenant may have as a guest in the rental premises and he cannot restrict visitors to the premises to certain hours, days, etc. Neither can the landlord restrict who the tenant may have as an overnight guest.
If the guest of the tenant is the cause of disturbing behaviour, compromises safety of the premises or interferes with the lawful right of others, the landlord may apply for arbitration to resolve the situation or end the tenancy.
If you intend to have your mother live with you permanently you my wish, if only for insurance purposes, to have her included in the lease agreement. This probably will satisfy your landlord too because his concern will likely be about knowing who he has occupying his rental premises.