My Friend ( Al, 75 Year Old Fellow No Long

My friend ( Al, 75 year old fellow no long term issues that I know of except for tinnitiis, ringing in the ear) called to cancel a dinner appt because he thought he had food poisoning. his symptoms are achiness, chills, pain across abdomen area, feverish, fatigue, no vomiting or diaregh yet. Just resting and staying warm and drinking water in hopes it will pass. Flu?