Wash strawberries and set aside 5-6 whole strawberries. Remove the tops from the remaining berries and cut into quarters. Set aside.
Wash and rinse blueberries and set aside.
Place 2 dollops of whipped topping into a piping bag fitted with a 1M star tip. Refrigerate.
Add milk and pudding together in a bowl. Whisk well until no longer grainy and smooth. Refrigerate for 5 minutes.
Cut the pound cake in half. Set aside one half. Cut the other half into slices and cut each slice into ½" cubes. Place cubes into the bottom of a trifle dish. Add half of the pudding on top of the cake and top with half of the whipped topping. Sprinkle with half of the cut strawberries and blueberries. Repeat layers, adding cake, pudding, whipped topping and fruit.
With whipped topping in the piping bag, pipe dollops on top of the trifle and top with whole berries. Sprinkle with red white and blue sprinkles. Serve immediately or cover and refrigerate until ready to serve.