Make a square directly above with masking tape about 10mm bigger than the hole. Rub a small amount of oil or furniture polish inside the square then cover with silicone caulk.

Once it's dry mark an arrow pointing up and peel the silicone off; That's your mould.

One you've got rid of the flakes fill the hole with wood putty and scrape off flat. Place your silicone mould on the putty lining up best you can so the vertical graining lines up then press the mould onto the putty to form the graining. Remove the mould and feather the edges with a light wet brush.

Once it's all done undercoat then light wire wool then paint the whole door.