Final answer:
Morphine is the medication that the nurse would choose for the older client with severe pain after a femur fracture.
Step-by-step explanation:
The nurse would likely choose Morphine for the older client complaining of severe pain after a femur fracture. Morphine is an opioid pain medication that is commonly used to alleviate severe pain in both pre and post-surgical procedures. It is highly effective in relieving intense pain and is often considered the gold standard for managing acute pain.