The church has detailed guidance on this.
I’ll try to summarise it for you:
Human life is a sacred, god given gift, form the moment of Conception, until the moment of natural death.
It must be nurtured and protected within and to the full extent of those boundaries.
Medical Intervention where is is available and normal, and does not violate other specific moral requirements is a tool that should be used to nurture and protect life.
However medical aid can be legitimately refused in a number of situations:
- violation of conscience: a treatment is immoral or you believe it to be (e.g. organs “donated” in a manner that killed or hastened the death of the donor. Organs taken without the permission of the donor, Treatments from embryonic stem cells.)
- Treatment creates an abnormal burden. Unnaturally extending the life of a person where there is no hope of recovery, and thereby increasing their significant and unavoidable suffering. Treatments which are so expensive that the persons entire family or community would suffer as a result of sacrificing the necessary cost.
The definition of “Normal Burden” vs “Abnormal Burden” is a complicated one which considers a range of moral issues.
The Church has given guidance on thisn in
Gaudium et Spes
DECLARATION ON EUTHANASIA
and
The Catechism
Here’s what the Catechism says:
From the Catechism:
2278 Discontinuing medical procedures that are burdensome, dangerous, extraordinary, or disproportionate to the expected outcome can be legitimate; it is the refusal of “over-zealous” treatment. Here one does not will to cause death; one’s inability to impede it is merely accepted. The decisions should be made by the patient if he is competent and able or, if not, by those legally entitled to act for the patient, whose reasonable will and legitimate interests must always be respected.
2279 Even if death is thought imminent, the ordinary care owed to a sick person cannot be legitimately interrupted. The use of painkillers to alleviate the sufferings of the dying, even at the risk of shortening their days, can be morally in conformity with human dignity if death is not willed as either an end or a means, but only foreseen and tolerated as inevitable Palliative care is a special form of disinterested charity. As such it should be encouraged.
Note that a paragraph 2278 is worded in the disjunctive, ie with an “or”, not an “and”. Therefore, such treatment can be legitimately refused is it is merely “burdensome”. It needn’t be dangerous and extraordinary and disproprotiaonate to the outcome also.
Any one of the factors is arguably sufficient to justify a refusal of treatment.