My cats eat a raw egg yolk every couple days...it's safe and doesn't go right through them.
Cow's milk dairy WILL cause diarrhea.....if you can get goats milk, that is better for them and won't leave a mess on the way out.
If you can't get any food.,...boil 2 parts white rice and 1 part chopped chicken (preferably the dark meat...NO bones). When done, blend it up, adding more water if needed to make it drinkable.
If need be, you may have to put some food on your finger and open the cat's mouth to rub it inside.....he HAS to eat. Then, as soon as a vet is open, if he is still not eating on his own, take him in. I'd take him in anyways just to be checked out to see if there is any reason he stopped eating.