The best advice I ever got about that kind of attitude was to always -ALWAYS - make it counter-productive. In other words, if he says, "Get me a drink now." Your response is a simple no. If he gets upset about it, explain that that kind of behavior does not get "rewarded." He can politely ask with the appropriate tone of voice and attitude and then he can be "rewarded." Or that you will NOT play with him until his attitude changes and he has a happy heart. NEVER give in, and always make his rude demands counter productive. Otherwise, you reinforce his negative behaviour. Even if you give in one time, he knows to keep trying it. 100% consistency and also, by the way, that your responses be spoken calmly and respectfully to him, so that he understands the appropriate way to speak to others as well. He knows, of course, but kids learn better by our deeds than actions. SO, even when that kind of behaviour frustrates the snot out of you, if you can remain calm yet firm in your response, it won't be a battle that he feels he needs to win, but rather a situation where he obviously has no choice but to change his behavior in order to get whatever it is he is hoping to get.