Euthanasia must be distinguished from the decision to forego so-called “aggressive medical treatment”, in other words, medical procedures which no longer correspond to the real situation of the patient, either because they are by now disproportionate to any expected results or because they impose an excessive burden on the patient and his family. In such situations, when death is clearly imminent and inevitable, one can in conscience “refuse forms of treatment that would only secure a precarious and burdensome prolongation of life, so long as the normal care due to the sick person in similar cases is not interrupted”. Certainly there is a moral obligation to care for oneself and to allow oneself to be cared for, but this duty must take account of concrete circumstances. It needs to be determined whether the means of treatment available are objectively proportionate to the prospects for improvement. To forego extraordinary or disproportionate means is not the equivalent of suicide or euthanasia; it rather expresses acceptance of the human condition in the face of death.
So Catholics don’t have to “pursue all means to prolong life.” What we must do, however, is pursue all ordinary means. “Ordinary” is a special word in Catholic moral theology: it is opposed to “extraordinary,” used in its original sense of “not ordinary.” To give an example from your own theology (as I understand it), you would say that baptism is “ordinarily” necessary for salvation, but that God can act “extraordinarily” and save even those who aren’t baptized (which, incidentally, is an example from Catholic theology as well)
One of the ways we distinguish between “ordinary” and “extraordinary” means is by distinguishing between “treatment” and “care.” “Treatment” is medical procedures such as chemotherapy, surgery, etc. intended to improve the patient’s condition. “Care,” on the other hand, is basic, non-medical acts to support life, such as regular bathing and feeding.
With that said, giving nourishment and hydration, even by way of a feeding tube, has been determined by the Church to be care, not treatment. It’s not intended to improve the patient’s condition, but instead to provide him basic necessities for life. Since it’s ordinary care, I couldn’t advise a doctor to remove or refuse to insert your feeding tube, should (God forbid) a situation arise in which you needed one.
To make an analogy, imagine that I had a severely mentally disabled child who was unable to feed himself. I would still be obligated (both as his neighbor and especially as his parent) to provide nourishment and hydration for him. Even if it meant spoonfeeding him for years, I would not be able to shirk that duty: he would starve without my effort, and his basic human dignity (not to mention my responsibility as his father) gives him the right to food. I would daily be living Christ’s commandment to feed the hungry and give drink to the thirsty: it would be an aspect of the cross I’d been given to carry. Now imagine that this child of mine one day awoke and was unable even to swallow. This change in his condition would not remove my obligation to provide him with the basic necessities of life. Even if the only way I could fulfill my obligation to him were with a feeding tube, I would still be obligated to provide him nourishment via that means, and I would still be obeying Christ’s command to feed the hungry and give drink to the thirsty.
I would be in a similar situation if you were suddenly to require a feeding tube. I couldn’t in good conscience advise medical personnel to withhold or remove a feeding tube, because to do so I would be denying you, not extraordinary medical treatment, but ordinary care that every human deserves. I’m not sure what the exact wording of your living will is, but if you were in a stable condition such that a feeding tube would be both necessary and sufficient to maintain that condition, I couldn’t advise that it be withheld or removed. Even if your living will were to direct the withholding or removal of a feeding tube in such a situation, my duty to give you ordinary care would override my obligation as your son to fulfill your wishes.
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