Above all, do not attempt to use science (I mean, the real sciences) as a defence against Christianity. They will positively encourage him to think about realities he canโt touch and see.
C. S. LewisStop it," spluttered Eustace, "go away. Put that thing away. It's not safe. Stop it, I say. I'll tell Caspian. I'll have you muzzled and tied up." "Why do you not draw your own sword, poltroon!" cheeped the Mouse. "Draw and fight or I'll beat you black and blue with the flat." "I haven't got one," said Eustace. "I'm a pacifist. I don't believe in fighting." "Do I understand," said Reepicheep, withdrawing his sword for a moment and speaking very sternly, "that you do not intend to give me satisfaction?
C. S. LewisBelieving things on authority only means believing them because you have been told them by someone you think trustworthy. Ninety-nine per cent of the things you believe are believed on authority... Every historical event in the world is believed on authority. None of us has seen the Norman Conquest or the defeat of the Armada.
C. S. Lewis