I never read any of his books. I Kissed Dating Goodbye wound up on our bookshelf somehow or another(*), but the Book of Mormon and the Bhagavad Gita sit there too, so you can't conclude much from its presence. On inspection, it isn't there anymore. Maybe it was a loaner.
I gather that IKDG was about maintaining purity, which in our super-sexualized culture is challenging. Any support our kids can get--and adults too--is useful.
The focus on "dating" seemed a little over-the-top; rather like "putting a hedge around the law." Not that I'm always averse to putting a bright line in the sand; I wrote a little about how that might have played out in the era of Judges.(**) Since I hadn't actually read the book, I didn't feel comfortable in judging it--especially since I was laboring under the delusion that he also wrote I Gave Dating A Chance (that was Jeramy Clark). But I was dubious--I suspected overreaction.
Maybe there were useful suggestions in the book. I can think of a few suggestions on my own(***): "date" in groups. Find something besides entertainment that you can do together--you learn more about people when they're a little stressed hauling prickly brush out of a widow's back yard than when they're dressed up at a restaurant. (Maybe I should charge for advice.)
If the news stories were correct, there were some problems in the pastorship, and then he got into some marital difficulty, and now has decided not to call himself a Christian any more. I thought one of the main points of Christianity was the opportunity and the power to have sins forgiven and get up and soldier on again. Maybe you learn something different in seminary.
Some say he got too famous too fast and too young. I could believe it. “I have lived a sort of backwards life. Without meaning to, I have experienced life out of the normal order and sequence of events.” He became a senior pastor at age 30, and was only 23 when he published his famous book--he didn't marry until 24.
(*) So did The Prayer of Jabez: I think somebody gave that one to us too. I never read that book either--it seemed disproportionate to the material, and I generally react against fads.
(**) The names in that piece are horrible. I tried for realism, and I shouldn't have.
UPDATE:(***) Added a phrase to clarify.