Reserve player of the year Duffy, 19, was forced to undergo life-saving surgery last Friday after lacerating his liver in a Republic of Ireland match against an amateur side.
Brian Duffy told the Liverpool Daily Post: "I said to him during the week, 'I don't know how I am going to watch you play again".
"What everyone did to save him was incredible. Nine times out of 10 Shane would have been lifted off the pitch to be examined. But that would have been too late, Shane would have been dead.
"John O'Byrne and Alan Byrne (the FAI doctors at the game) had the good sense to get him on that stretcher and down the road as soon as possible.
"We almost lost him in the ambulance, but when we got him here the crash team were standing waiting for us, we hadn't got him in the door and they were working on him. It was just a complete unit, right down to Gerry McEntee doing the surgery.
"I tried to thank him the next day for what he had done but he said that it was the people before him that had done the hard work. He was just a very humble man but he was fantastic, they all were, I can't thank them enough."