The decision in this scenario is complex, one would need information about the patient's condition, medical history, and other critical factors that could affect their treatment.
However, medical professionals are bound by ethical principles and guidelines that prioritize the well-being and autonomy of their patients. In this situation, the decision should be made based on the best interests of the patients involved and their autonomy to decide about their own treatment.
One possible approach is to explore alternative options for the patient who needs the medicine, such as seeking out other sources of the medication or exploring alternative treatments. If these options are exhausted and the patient's condition is dire, it may be necessary to administer the medicine to save their life.
It is also essential to consider the ethical implications of using organs from a deceased patient for transplantation. Organ donation should be voluntary and informed, and the decision to donate should not be influenced by external factors such as the potential benefits to other patients. The decision to donate organs should be made separately from the decision to administer medicine to the sixth patient.