Preheat oven to 350 degrees F (175 degrees C). Grease a 9x13-inch baking pan.
Combine brownie mix, oil, eggs, and water in a large bowl. Mix with a wooden spoon or spatula until well-blended, about 3 minutes. Pour into baking pan and spread evenly.
Bake in the preheated oven until toothpick inserted into the center comes out clean or with a few moist crumbs attached, 28 to 31 minutes. Cool completely, about 30 minutes. Cut into 1-inch squares.
Place half of the brownie squares at the bottom of a trifle bowl or glass serving dish. Layer half of the cherry filling on top. Top with half of the whipped topping. Repeat with remaining brownie squares, cherry filling, and whipped topping.