Thank you for sharing your situation and question with us.
We can appreciate that you would be interested in this type of information. It is really important that you be aware of what you and your mother’s rights are in this situation.
A landlord can raise the rent every twelve months by a percentage that the provincial government sets. The landlord must give the tenant a written notice at least 90 days before the rent goes up.
It is important to note that, the guideline does not apply to some newer rental housing.
Regarding the situation you mentioned, where a guest is staying in a rental unit, you can find some very helpful information on the Landlord’s Self-Help Centre website. The Landlord’s Self-Help Centre is a non-profit community legal clinic which supports Ontario’s small-scale landlord community exclusively.
Here are some excerpts,
It is best that before you or your mother agree to or sign anything that she contact the nearest Community Legal Clinic for free legal advice and some assistance.
I hope this information is helpful. Please let us know if you have further questions and if there is any follow up to your question/situation.