He hints at a claim held by others to the opposite: that morphine doses can be subtly increased to function as a form of assisted suicide, a.k.a. euthanasia.
Canadian law makes a distinction based on the doctor' intent: they're allowed to give morphine in order to manage pain, even if that shortens life.
The following quotes are from Parliament of Canada - The Special Senate Committee on Euthanasia and Assisted Suicide - June 1995
The Canadian Bar Association referred specifically to the legal status
of terminal sedation as a medical technique to control pain
The policy of the Ontario coroner is illustrative of the practice in
this regard. Palliative care that results in death is not considered
to be criminal, so long as four conditions are satisfied: (1) the care
must be intended solely to relieve suffering; (2) it must be
administered in response to suffering or signs of suffering; (3) it
must commensurate with that suffering; and (4) it cannot be a
deliberate infliction of death. Documentation is required, and the
doses must increase progressively.
There is no precedent in this area. There have never been any legal
convictions for providing such treatment and although there are no
decided cases on point, a reference was made to the practice of
providing potentially life-shortening treatment with the purpose of
alleviating suffering in the Rodriguez case. The real issue in that
case concerned assisted suicide under section 241 of the Criminal
Code. Mr. Justice Sopinka, writing for the majority of the Supreme
Court of Canada, however, drew a legal distinction, based on
intention, between the administration of drugs that are likely to
hasten death on the one hand and assistance in suicide on the other.
Without deciding the issue, by implication he seems to have suggested
that if the intention is to alleviate suffering, it is legally
permissible to provide treatment notwithstanding that this may hasten
The above says, "potentially life-shortening" and "likely to hasten".
Some of the paragraphs after that imply that the expert witnesses disagreed about whether it will in fact shorten life, for example:
Professor Schafer, testified: If we think about it, what the
palliative care physician frequently does in giving an adequate dose
of painkilling medication is hasten the death of the patient, entirely
justifiably in my judgment, and entirely justifiably in the judgment
of every one of my philosophical and legal colleagues whose briefs I
Dr. Macdonald stated: Another area of confusion is whether or not we
are killing the patient with these drugs. That was a subject of
correspondence I had with the committee. People think, for example, if
we increase the dose of opioids so that a person is stuporous, we may
kill the patient if we give them a little more. In my experience, that
is highly unlikely to happen. Patients rapidly become tolerant to the
respiratory effects of opioids, morphine and like drugs. If we give
them a large dosage of a drug, we may sedate the patient but it is
unlikely that the patient would die of our drug. They may die of
pneumonia or an associated problem which sedation might make more
likely to come about, but to die directly of a drug effect is unusual.
The last two sentences above implies that it shouldn't cause death directly, but may indirectly.