Based on the text in the twelfth chapter of the book, why does Frankie feel justified in treating Aunt Concetta's death as an uneventful occurrence in his life as well as that of Penny's?

Based on the text in the twelfth chapter of the book, Frankie feels justified in treating Aunt Concetta's death as an uneventful occurrence in his life as well as in that of Penny's because neither he nor Penny knew her very well.