Hi. Thanks for asking in Healthcare ,agic. As long as he has fever he should avoid fatty food and eggs. Bland diet like toasted bread, rice gruel, mashed potatoes, banana, apple, vegetable soup and mashed potato are ideal. In fever, already the BMR will be high. Improper and heavy diet will further increase the BMR and can result in indigestion. Generally, the cough will be present for few more days. Cough usually continues till the sputum is completely cleared from the lung. But, if it is persistent, then you should consult your treating Dr. to find out the cause. Dry cough will subside for anti histamines like Levocetrizine and Linctus Codiene. Antibiotics can also cause dry cough. He needs adequate rest, proper diet and plenty of fresh fruits and fruit juice. I hope this is useful to you.