Actually, part of the breakdown David experienced when he finally got home was the conflict he felt between reviling what his parents had done to him, and wanting to win back their love. Before he even got home, they were suing the filmmaker and her university. They managed to delay but not stop the film.

From what I was able to dig up, they have managed to keep some kind of a relationship intact, but if they have ever apologized or expressed regret for what they did, I haven't been able to find it.