I have 2 4 week old kittens. One of them will eat the food that you water down and add a little soft food. The other will only eat the hard food. The problem is that he can only suck on it and then spit it out because he can't chew. How or what can I do to get him to eat?

So one only eats hard food and one only eats soft food?

Just give one soft and one hard :confused:

Or is the kitten having trouble eating ANY food?

Have you tried them with kitten food?
My cats last litter wouldn't eat anything except tuna from a tin.. they do gradually eat more though as they get older