Canada has a 90-day assessment/waiting period for those whose deaths are not reasonably foreseeable. They won't euthanize you unless you seem capable of making the decision and have thought through it for an extended length of time. It's not an impulsive thing.

But, isn’t it their choice? If they are adults, and have lived at least a few decades..

I’ve never figured out why we as a society want to impose our morality on others.