He would probably be fussy and would not want to eat. This could be a strangulated hernia, an emergency. Infants do very well with surgery. Children who are old enough to talk are sometimes anxious if they don't know what will happen to them. You can ease this fear by talking about the upcoming surgery.
Many local libraries have books or video tapes about going to the hospital or doctor's office.
We also have a video tape which can explain the Outpatient Surgery Center to children. Children are often fearful of an unfamiliar environment. It may help to bring a favorite toy or blanket on the day of surgery. Like children, parents also are sometimes anxious about the unknown. Don't hesitate to ask questions.