Before revision: "...und wenn sie nicht gestorben sind, dann leben sie noch heute" (and if they are not dead , then they are still alive today), traditional German formula to end a fairy tale (like "they lived happily ever after").
After revision: "...und wenn sie nicht gestorben sind, dann leben sie noch heute" (and if they have not died , then they are still alive today), traditional German formula to end a fairy tale (like "they lived happily ever after").