Specifically to this, tell him nothing or, at least, nothing for you. More generally, if you don't want to argue, simply don't. That is a choice you make. Concerning messes, I only see this as a problem for you if you have to share a room with him. If not, let him and the rest of your family leave the mess as it is. If you clean up after him, you're enabling the messiness to continue. If you say anything about it, then, first, you're opening up an opportunity for argument, and second, you're showing anger with which he and your father can laugh at.

You asked for advice on what to do. Well, the best thing to do in this case is nothing. They seem to take you for granted. By doing nothing, perhaps they'll realize how much they rely on you. And if they don't, you'll still eliminate the anger.