Welcome, Rosetta. The actor's name is Livio Georgi, and I believe he really sings. You can also hear him singing on the steps of Vito's tenement after Vito kills Fanucci and says, in Sicilian, to the infant Michael, "your father loves you very much."
Ntra la porta tua lu sangu � sparsu, E nun me mporta si ce muoru accisu... E s'iddu muoru e vaju mparadisu Si nun ce truovo a ttia, mancu ce trasu.
