Derek Humphry wrote, as part of a defense of Physician-Assisted Suicide (PAS):
The help of a physician [in PAS] is imperative, because loved ones and family members untrained in the medical profession are rarely able to help a loved one to die [...].This idea seems a standard part of the arguments for PAS.[note 1]
But there are four ways of reading "able" in "able to help": morally, legally, technically or psychologically, as well as combinations of these. Hymphry is presumably not claiming that family members are morally unable to help, that it is wrong for them to "help", since it would be really weird to suppose that medical training somehow gives one permission to kill when before the killing would be immoral. Nor is he claiming that unlike physicians they are legally unable to kill, for instance because they would be charged with murder, since the legality of PAS is precisely what is at issue, and if PAS is illegal, then physicians are also legally unable to "help".
Probably the best reading is "technically able to help", given the mention of training. But on that reading, the claim is false. There are many highly reliable methods of basically instaneously killing a person, at least if the killer has a normal amount of dexterity and physical strength. At the expense of some gruesomeness, let's briefly mention shotguns and large axes. One might object that in those cases, it is not a matter of helping but a matter of doing the whole job oneself. But it is easy to give the victim a role, say having the victim pull the trigger with a string.
Perhaps, then, we should read "able to help" as "psychologically able to help". On this reading, medical training makes it psychologically possible to kill. This is scary in that it makes medical training be akin to military training, a regime that makes one into someone who is not merely technically but psychologically capable of killing, overcoming our innate resistance to killing (on the latter topic, see this fascinating book by Rachel MacNair). Besides, if psychological resistance is the issue, one doesn't need a physician, just an able-bodied psychopath.
Maybe the best reading of the quote from Humphry is to combine the technical and psychological. The technical skills of the ordinary person, just much as those of the physician, make possible multiple relatively painless methods of killing, but these methods are messy, and are likely to be traumatic for the perpetrator. The methods available to the physician are neater. I think, though, there is a more perspicuous way of putting the difference: The methods available to the ordinary person make it look like the family member has killed a person, while the methods available to the physician make it look like a medical procedure has been performed. But once we formulate it in this way, it seems that the main "advantage" of the methods available to the physician is that they hide what has happened—the destruction of a human body. And that, in turn, is no advantage at all, since it hides from the moral imagination the truth of the situation, thereby skewing the decision.
Objection 1: Humphry could simply be worried about cleaning up after a killing committed with an axe or a gun.
Response: That seems unlikely. Besides, if mess is the issue, someone formerly in the special forces could surely be hired to do a neat and instantaneous job. Physicians are not the only people with technical skills for killing.
Objection 2: Being killed medically is more dignified than being killed with a gun.
Response: I simply do not see this. Why should being poisoned by an injection administered by someone in a white coat be more dignified than being shot dead? After all, we think of soldiers in wartime as dying with honor and dignity when they are shot by the enemy. I think the issue is not that being killed medically is more dignified, but that being killed medically hides the truth about what is happening. And dying in such a sneaky way is, if anything, less dignified.
Final comment: If I am right, then a major reason for PAS is a desire to make killing look less like a killing. And that desire is illegitimate if PAS is morally permissible. At the same time, I think the presence of that desire reflects something good: it reflects a revulsion at killing. But to kill the patient in a way that hides the destruction of the body is not the right way to respond to that revulsion. The right way to respond to that revulsion is to recognize the dignity of human life, and to care for rather than kill the patient.