What exactly does church teaching say about keeping someone alive when - DNR's (do not resuscitate) and such? I know food and water can't be denied (like in the Schiavo case), but what about things like respirators? When is it morally acceptable for someone to be allowed to die and no longer considered murder/suicide?
Also, if a Catholic has non-Catholic parents who do not want to be resusciated/kept alive in certain situations (both my parents have discussed this with me), is said Catholic morally allowed to see to it the parents' desires are fulfilled? To what extent can that Catholic go to make sure such wishes are followed-through with?
I found these two articles:http://www.catholicapologetics.info/morality/deathpenalty/euthan.htm
"Everybody has the duty to employ what is necessary to the conservation of his own life and health, to avoid what is harmful to them, and to use what can restore the health. ... Everybody has the duty to conserve his own life and health by ordinary means. This principle is just a consequence of the precedent. The ordinary means are the means that are commonly used by men to preserve their own life, and which can be procured by ordinary diligence.
"What are these ordinary means today?
-ordinary surgery, etc."http://www.ewtn.com/expert/answers/end_of_life_decisions.htm
"The key principle in this statement (i.e. CCC
, n. 2278 ) is that one does not will to cause death. When a person has an underlying terminal disease, or their heart, or some other organ, cannot work without mechanical assistance, or a therapy being proposed is dangerous, or has little chance of success, then not using that machine or that therapy results in the person dying from the disease or organ failure they already have.
"We must, therefore, ask the question "will the withdrawal of nutrition and hydration allow the person to die, or kill the person?" When it will allow a person to die from an underlying condition, rather than unnecessarily prolonging their suffering, it may be removed. So, for example, in the last hours, even days, of a cancer patient's life, or if a sick person's body is no longer able to process food and water, there is no moral obligation to provide nutrition and hydration. The patient will die of their disease or their organ failure before starvation or dehydration could kill them.
"However, when the withdrawal of nutrition and hydration is intended to kill the person, or will be the immediate and direct cause of doing so, quite apart from any disease or failure of their bodies, then to withdraw food and water would be an act of euthanasia, a grave sin against the natural law and the law of God."
With regard to your parents, I would say that you are obligated to make sure they get the ordinary means that are necessary to sustain life. Hopefully somebody else will be able to chime in and give you a more detailed and complete answer.