I have in fact given medical assistance in dying to several patients with dementia who clearly retained their capacity until the last minute, but who would definitely have liked to spend a little more time with their family. If they had been able to make an advance request, the criteria they would have chosen would have been not being able to care for themselves or recognize their family members, which would have left them quite a lot of additional time. It can indeed take months and sometimes even years in some instances before reaching that state.
I think people have heard about the case involving Ms. Demontigny, who is fighting for advance requests. She is fighting for the additional years she might have.
I have indeed had patients who received medical assistance in dying too soon, as it were, because they did not have the opportunity to complete an advance request.