Mix coconut, cake mix, and butter until crumbly. Pat lightly into a floured 9×13-inch pan. Bake 10 minutes at 325 degrees. Pour apple pie filling evenly over warm crust. Mix together cinnamon and sugar. Sprinkle over apple pie filling. Mix egg and sour cream until well-blended. Pour over cinnamon and sugar. Bake at 325 degrees for 25 minutes.