Satan Die why?

Sometime we will happen to sit with mental problem and people with a bit of retard. Actual there are many more kind of people you will see on the tain. Today i sitting with one guy in the train. He was talking very loudly to himself " God is real, who are you, where are you. Satan ! Kill u Kill u ! Satan you die !" This let me think what acutal happen to this guy? Did he really see god and god say something to him or is he actually a crazy fellow? But i still think he was too stress and become in this state. There are so many bad things in the world, if one really bad one falls on you will you be able to stand up again and live your life?