Final answer:
In this scenario, the elderly man has a living will stating that he does not want invasive medical procedures. Mechanical ventilation should not be instituted.
Step-by-step explanation:
In this scenario, the elderly man has end-stage emphysema and pneumonia, and his condition is deteriorating. He has a living will on file which states that he does not want invasive medical procedures that would prolong his death. Since no surrogate decision maker is available, the medical team should honor the patient's wishes as stated in the living will. Therefore, mechanical ventilation should not be instituted in this case.