Final answer:
The nurse's priority is maintaining airway and breathing for a client with advancing ALS.
Step-by-step explanation:
The nurse's priority in caring for a client with advancing amyotrophic lateral sclerosis (ALS) is maintaining airway and breathing. ALS is a disease that affects motor neurons, leading to muscle weakness and eventually paralysis, including the muscles involved in breathing. Therefore, ensuring the client's airway is clear and their breathing is supported is crucial for their survival and well-being.