If you want to keep from giving his soother back to him, you may be able to substitute something else such as a favorite blanket ,or a cuddle toy. Children this age feel secure when you have a certain routine that is followed each time when they are getting ready rest or to fall asleep. Going through the same routine in the same order each time will help to prepare him to rest or sleep. For example, brushing his teeth, followed by reading 3 or 4 books. Allow him to choose the books and let him know that after you read the books to him it will be time for him to lie down and keep his head on the pillow. He may not go to sleep necessarily, but he must lie down and be quiet. Many children around this age stop napping or don't always fall asleep.The routine is the key. Sleeping is not always necessary, but being restful and quiet will still be good for him and help you to establish discipline and security with him. Playing a music box or something else soothing after the books may help too. It is especially good if you can find one that he can wind up himself. He may play it over and over agin, but that is okay as long as he is otherwise quiet. The napping isn't what is important as long as he has a rest time. Most children will eventually wean themselves from the soother, so it isn't the end of the world if he requires it again, but you can try these other things first. Also it is important that you stay calm in this because he will sense your tension which makes him less apt to rest or sleep.