I certainly encourage people to carry a Bible or New Testament with them if they can -- but not for the reason your friend is doing it. The Bible is not a good luck charm, and we shouldn't use it as such. In fact, the Bible tells us not to trust in any object that supposedly has mystical or occult powers: "This is what the Sovereign Lord says: I am against your magic charms with which you ensnare people like birds" (Ezekiel 13:20). Our trust is to be in God, and God alone -- not in some man-made idol or charm. When we become fascinated with such superstitions, we lose our trust and confidence in God.
And we can trust God with our lives! He loves us, and we are never beyond His knowledge or care. Jesus' promise is true: "And surely I am with you always, to the very end of the age" (Matthew 28:20). When we know Christ, we know He lives within us by His Holy Spirit. Why put your faith in some inanimate object (even one that is religious), when God is with you?
Encourage your friend to put his faith and trust in Jesus. Only He can take away our sins, and when we know Him, we are safely in His hands forever. Then encourage him to begin reading his Bible -- learning God's promises, and discovering how He wants us to live. And if you have never given your life to Christ, don't let another day go by without Him in your heart.