What do you think? Advice, suggestion...

I have a friend whose parent is exibiting some strange behavior. The parent basically would make some loud strange noise and cause everyone in the house to panic and it turned out to be nothing. Also he would behave very good at the presense of guest and then behave really bad (not really his character) when he is with his family alone. He would throw tandrum for no unknown reason.

I am a prenursing student and I am curious what I would look for if I were a nurse. Also what kind of family teaching that can be done?