I find the highlighted text a bit weak--there's no real safeguards that would keep this from happening.
Also, there should be some stricter methods to determine whether the paitent is "mentally competent" or not.
And I totally agree with evergreen re: letting the paitent actively trigger the procedure themselves.
Logically, I can't make an argument against this. If the person is clear of mind, without a doubt consenting to have this done, and there's no chance things will improve, what grounds could I oppose this? But philosophically, I find it very hard to support this. The cold finality of death seems, shall we say, above our paygrade in some way. It feels like taking the Grim Reaper out on a dinner date. For the entire existence of living things we've been trying, first and foremost, not to die. Maybe that's why this feels wrong?