Combine jam and water in a medium bowl; stir in raspberries and strawberries. Reserve 2 tablespoons berry mixture for topping. Tear brownies into small pieces, reserving several pieces for topping.
Place several brownie pieces in each of 4 dessert cups. Spoon about 1/4 cup berry mixture over brownie. Repeat layers. Top each with whipped topping, ice cream topping, reserved berry mixture, and reserved brownie pieces.