The Christian LARP is only done because they're banking on the concept of forgiveness and non-judgment. The amount of people that go to church but don't do any of their own research and think, "it's wrong of me to doubt intentions," because some other Christian LARPer told them that is ridiculously high.
He can believe in God all he wants. He can even claim God has personally forgiven him and quote scripture all he wants. He hasn't walked away from his sins, though. He isn't even a private sinner, like all the Christians still addicted to porn or drugs. He's an open, proud sinner that still spouts scripture.
He should really pay attention to the scriptures that talk about being lukewarm and God spewing them from His mouth.