If the breeder has a mentor guiding her that would be good to know. If it is just someone doing it without any thought or study then I would be wary of getting a puppy from them line-bred or not
If you really get interested, an awesome book is Claudia Orlandi's ABCs of Dog Breeding (she also does a seminar with that title). I think it is self-published though, but you can get it through her site if you google her name. I breed my dogs only on a very limited basis but I try to digest as much info as I can about it, from books, seminars and experience breeders. Of course I tend to get a bit obsessive so I also end up doing research on all sorts of things I never intend to do myself, just for the sake of knowing a little more about something! So you can tell your husband you are not the only one who gets curious about stuff they don't do themselves!