Although it might not occur in everyone, alcohol is a depressant that can alter your moods. It can also cause poor concentration and reaction, or poor coordination.
That means they could've cheated or broke up and if they don't reply to you in a while just move on and say I want to break up with you because that's sketchy stuff
The nurse should respond by telling the teacher that something is seriously wrong with the child and to possibly call the child's parents to have her checked out by a doctor.