Well... I imagine DeWolf was pretty angry with his father, and he probably had some pretty good reasons for being angry, and I have personally been known to say and do stupid things out of anger, but I really don't know in his case.
As for why he recanted, well... I don't know why, either, but I don't doubt the church brought a lot of pressure on him.
Without reading the book, however, I can't comment on the "truthiness" of it. *grin*