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. LewisThe sun looks down on nothing half so good as a household laughing together over a meal.
C. S. LewisIt is in some ways more troublesome to track and swat an evasive wasp than to shoot, at close range, a wild elephant. But the elephant is more troublesome if you miss.
C. S. LewisI have come," said a deep voice behind them. They turned and saw the Lion himself, so bright and real and strong that everything else began at once to look pale and shadowy compared with him.
C. S. LewisI do not think that all who choose wrong roads perish; but their rescue consists in being put back on the right road. A sum can be put right: but only by going back til you find the error and working it afresh from that point, never by simply going on. Evil can be undone, but it cannot 'develop' into good. Time does not heal it. The spell must be unwound, bit by bit, 'with backward mutters of dissevering power' --or else not.
C. S. Lewis