Hello i had go e through your question and i appreciate your concern he needs a well balanced diet to boost his immunity as well as speedy recovery I would advise you following plenty of fresh fruits and steamed or raw vegetables boiled eggs steamed and we ll cooked meat adequate amount of dietary fiber and probiotics advise him to have 2 to 3 litres of fluids like fruit juices regular bowel movement is very much required so he can be given stool softening agent or laxatives hope.this helps him please feel free to ask for more clarification best wishes Dr BR Hudda