I don’t see the book mentioned as much as say, books by Pigliucci or Robertson, but if one were to ask me where to get started with the philosophy, Seddon’s book would be the one I would recommend as the first guide.
If dad wasn’t happy, nobody got to be happy. For most of my adulthood, I’ve had to act as a sort of parent to him, being the person who keeps him from going off the deep end when he was heavy on drugs and suicidal.