Treatment of cholecystitis depends on the severity of the condition and the presence or absence of complications. Uncomplicated cases can often be treated on an outpatient basis; complicated cases may necessitate a surgical approach. Antibiotics may be given to manage infection. Definitive therapy involves cholecystectomy or placement of a drainage device; therefore, consultation with a surgeon is warranted. Patients admitted for cholecystitis should receive nothing by mouth because of expectant surgery. However, in uncomplicated cholecystitis, a liquid or low-fat diet may be appropriate until the time of surgery.

Your description suggests he is having severe cholecystitis, In such inflammation food is restricted. Any oral intake leads to complications.