Final answer:
Engaging involved staff at all levels in the decision-making process is the best approach to assess and adapt the medical unit to better meet the unique needs of older adult patients.
Step-by-step explanation:
The best approach to assess and adapt the medical unit to better meet the unique needs of older adult patients is to engage involved staff at all levels in the decision-making process. This approach aligns with complexity principles, as it recognizes the value of input from multiple perspectives and promotes collaboration.