It's up to the patient in question, and, as stated before, should be determined by how painful low life will then be i.e. Some of has taken a little to many drugs and now feels depressed. When taken to hospital (Drugs are baaaaaad) they beg the doctor to kill them. An absoulute no-no

But in the case in the first post, a Death Doctor should be allowed to "Assist" them in choosing what they want.