Not only is he a heretic, he's a coward. The scriptures are very clear on the miraculous birth of Jesus.
I guess it would be more "heroic" to just keep all of his doubts to himself? I agree that he should find a new job, quit this one, and then say what he thinks. But if everyone who had doubts about certain aspects of their faith was concidered a coward, only "heros" would be left. And their numbers would be very small.