Final answer:
The person assisting the patient should encourage slow, deep breaths and instruct the patient to cough forcefully.
Step-by-step explanation:
When assisting a patient with coughing and deep breathing, the person should encourage the patient to take slow, deep breaths and tell the patient to cough forcefully. Deep breaths, called diaphragmatic breathing, require the diaphragm to contract, while coughing forcefully helps to expel mucus and other obstructions from the airways. On the other hand, instructing the patient to take shallow breaths or advising them to hold their breath are not effective techniques for aiding respiratory function.