If your husband is of a heavy build I would concentrate on broth and tea. (his body has plenty of stores to keep him going and it may be beneficial for him to enter a fasting state.) If he is not, then think baby foods, meats and veggies mashed, stay away from sugary foods, bread, pasta, cakes etc, keep the inflammatory carbs to a minimum.
Quinnine from tonic water, or boil grapefruits and lemons (youtube has recipe) vit D zinc and selenium, try the master flu tonic (its on here -look it up) elderberry tincture. Make him lie on his front leanining down to drain the fluid for 20 mins every hour, look for herbal teas with mullien and horehound or any cough mixtures that have a suppressant to save hime damaging his chest, essential oils that help breathing, and look up mustard plasters and white onion plasters as well.