answer: Mr. Hudson is not as cheerful as usual. #Person1# and #Person2# figure out that it's because he's worried about his son.
documents: #Person1#: I think something is wrong with Mr. Hudson. He's not as cheerful as usual.
  #Person2#: I don't know what it could be.
  #Person1#: I heard last week that his mother had been ill. I wonder if that's the trouble.
  #Person2#: I doubt that. Yesterday he told me his mother felt much better.
  #Person1#: Maybe he has a problem here at work.
  #Person2#: I don't think that he has any problems with his job. It's well-known that Mr. Hudson is the best worker among us.
  #Person1#: Perhaps there is some trouble in his home.
  #Person2#: Well. The headmaster phoned this morning.
  #Person1#: That must be the problem. He's worried about his son.