Caught drinking and driving?

So i have a friend who was recently caught drinking and driving. He was at a McDonalds eating with friends in his car because it was 3:00am and they were hungry but did not want to go home. Next thing you know, a police officer pulls up and says he smelled alcohol. He was obviously lying becausr they had stopped drinking at the time. So he gave my friend the walking test and the eye test. He failed both! The cop was really nice and let him go. Is there anythung he can do now if he changes his mind. Let me add hes underage drinker!