What if they are in constant mental pain and anguish, but otherwise a sane person?
no justification required. you want out? ok, cya bud.
If only there was another way... We can't fix it now, but if we could put that person in suspended animation or some other kind of stasis, we might revive them once treatment was available...
This all is really sad and I don't wish anyone to suffer. But I also don't want people to die because they thought their situation is hopeless and it might turn out it isn't...