There are no right or wrong answers here, but before we help heal someone we should consider what is best for the patient. (They usually know better than we do!) Did the patient ask for our help? What are their beliefs on the afterlife? Do they welcome death as a type of "graduation ceremony" or do they truly wish to live? While it may not always be possible to communicate with the patient, hopefully we know them well enough to understand their wishes. It may be wise to discuss these matters with loved ones beforehand. Many people have a Living Will; does the same concept apply to the use of magic?
While most Pagans speak of Karma and reincarnation, many of us were born into a society where death is feared, rather than accepted as a natural part of the cycle. The fear of death may be the root of our desire to prolong life for our loved ones. A healer should always examine their own motives for wanting to heal. Is it because we truly want to help, or is it because we are afraid of being alone?