Doctors must carefully consider withdrawing life support to avoid directly killing or prolonging life unnecessarily. Treatment should only continue if it provides proportionate benefits compared to the burdens, and is beneficial, useful, and required rather than disproportionate, burdensome, useless, or optional. Questions remain on whether removing feeding tubes constitutes directly killing or allowing to die that could impact views on cases like Nancy Cruzan's removal of her feeding tube in light of Catholic teachings.