One way to counter this argument is to ask your friend to read through the four gospels and create a chronological timeline of Jesus' life that is truthful to and leaves nothing out of all four gospels. After he does that(hint: it's impossible) then ask your friend if the books truly agree with each other.
Even if the open windows of science at first make us shiver after the cozy indoor warmth of traditional humanizing myths, in the end the fresh air brings vigor, and the great spaces have a splendor of their own - Bertrand Russell