I think they need to talk to at least get an understanding of each other, but if nothing is resolved then he has every right to just walk away. I should probably encourage him to be as successful as possible in order to show them that he doesn't need religion (his dad once told him that they wouldn't have what they have without religion) in his life, or them if they're going to constantly berate him for his lack of religious beliefs.
Christian apologetics is the art of rolling a dog turd in sugar and selling it as a donut.
