Find a desk lamp. The one with the yellow light bulb before. Switch to a 40-watt light bulb. Put it outside the cage. Let the environment where he is locked up warm up. Find a cloth. Cover it. Leave a vent.
If he still eats by himself, he will go to the place where pigeons are sold, buy pigeons and tell the pigeon seller about cold medicine.
Take a little at a time and mix it in the food.