My Father Was Diagnosed With Liver Abcess Last Month. The

My father was diagnosed with liver abcess last month. The abcess was around 6 cm. He was admitted later and was treated under antibiotics. He was discharged last week after being shown considerate improvement of the abscess. He was aspirated twice( 100 ml and 30 ml). The recent ultrasound reports are showing improvement. Most of the symptoms are gone except the tendency of nausea. I need to know some info about a proper diet of 55 yr old(non diabetic) person. And how much time will it take to recover fully from the fatigue ? Thank you