Coat a 9x13 baking dish with cooking spray. Preheat oven to 350 degrees F (175 degrees C).
In a large bowl, combine eggs, 1 cup sugar, milk, cinnamon and nutmeg and stir until smooth. Fold in peaches, apples and bread cubes, until bread is well coated. Pour into prepared baking dish. Dot with 6 tablespoons butter.
Bake in preheated oven for 1 hour, until set. Serve warm with whiskey sauce.
To make whiskey sauce: In a medium saucepan over medium heat, combine whiskey, 1 pound butter and 2 cups sugar. Cook and stir until sugar dissolves and sauce is smooth. Remove from heat and serve hot.