I live this in my work every day Lar. It would be presumptuous of me to assume that I know what your mother is thinking, but you have to attempt to do your best to put yourselve into her shoes. I commend you for respecting her right to self-determination (social work-speak, but an intuitive concept nonetheless). Even after mental incapacitation most us us would want to have decisions made on our behalf made as if we ourselves were making them. This is the foundation principle of advancce directives (called substitute judgement). Has your mother executed a Power of Attorney for Health Care (if such a thing exists in Canada)?

I wish you both the best.
Topher