Who can be trusted?

One of the main characters, is the Man. I do not trust him or his health. The Man seems rather aggressive and paraniod that everyone is following him and his son, as they are trying to survive the barron wasteland that they now call the world. As they travel they come across other people that are just trying to find supplies and eat. The Man begins to agressively question them as to how long they had been following him and his son, and why. This leaves me with reason to believe that he may become untrusting of his son aswell. My reasoning for not trusting his health is because he continuously speaks to god about meeting him at last, and asks him if he has a heart or soul. I believe he asks these things because he is very ill and wants to know how much time he has left with his son before the sickness finally takes his life.