Over the years, I've discovered that people who don't want to turn their lives over to Christ will latch on to anything -- no matter how far-fetched or unreliable it is -- to use as an excuse for their unbelief.
I suspect this is true of your friend -- because the evidence for Jesus Christ and for the reliability of the Bible is overwhelming. Remember: When the Gospels were written, countless thousands were still alive who had witnessed His miracles and heard His teachings. If the Gospels were inaccurate, they would have been dismissed immediately -- but they weren't. The apostle Peter put it this way: "We did not follow cleverly invented stories when we told you about the power and coming of our Lord Jesus Christ, but we were eyewitnesses of his majesty" (2 Peter 1:16).
It's true that even from the beginning some have tried to distort the message of Christ, often attempting to combine it with other beliefs. Paul warned one group of Christians, "Evidently some people are throwing you into confusion and are trying to pervert the gospel of Christ" (Galatians 1:7). We shouldn't be surprised at this; Satan will always try to confuse people and turn them away from Christ.
Never forget: Jesus Christ is the center of our faith. He was God in human flesh, and He came from heaven for one reason: to save us from our sins. Pray for your friend, that he too will make Christ the center of his life.