Riddle

A plane holding multiple men and their sons crashes alone in the woods on the border of the USA and Canada. One of the surviving sons with two coins (one of which is NOT a nickel) totaling 30 cents in his pockets is rushed to the hospital and the surgeon refuses to operate, saying, "I can't operate on my own son!" What two coins are you paying the surgeon to get the surgeon to explain the meaning of the comment and also to get the surgeon to answer that if this plane crashed in the woods without anyone around, would it make a noise where you bury the survivors?