Help with Abandoned Kitten?

You say the kitten has some of his teeth. That makes him at least four weeks old now. At that age, you can try introducing him to canned food mixed with milk. Maybe you'll have more success with getting him to eat than you did by using a dropper. Not all kittens take to bottle/dropper feeding and while it's not the best situation, he can now learn to eat like an adult cat does.