I started following the ketogenic diet used by Dr. Eric Westman from Duke University. It's under 20 carbs but gives extra guidelines which I wanted. There is a link to a video where he explains it, and we downloaded his diet from Amazon. I'll find the links.
Here is the link to his diet on Amazon, I was able to download the kindle version for free: http://www.amazon.com/Low-Carbohydrate-Ketogenic-Diet-Manual/dp/1482781255 This is a YouTube video of him explaining the diet: https://www.youtube.com/watch?v=dSLf4bzAyOM
It really is just basic keto with some extra guidelines (some things are more limited). He's written some books too, but I haven't read them.
I do know that people on insulin need typically medical supervision on keto (their need for insulin becomes reduced) so your dad takes insulin he would probably want to talk to his doctor. I'm only on Metformin and don't need any medical supervision to do a ketogenic diet. My blood pressure improved so much I may not need blood pressure medicine very soon. If he is able to try it, he may see huge benefits and the benefits are often seen very quickly (even before losing a huge amount of weight). I think anyone with diabetes should at least know about this diet in order to know all their options.
I hadn't thought of Westman's book as it is very small and basic (and the info is all available online). But you are right, if someone doesn't want any theory, just the facts needed to get started, it's the best I know of.
I hadn't heard of Keto Adapted but given the forwards by Davis and Pearlmutter, I would guess it is great. To bad it is only an e-book. I may break down and buy it anyway.
I would guess that if OP just wants to start, Westman is the book. I "Looked Inside" Emmerich's book and it looks really solid. A good follow up to Westman. Once those two were consumed, Ruhl would be my next choice if the desire is just "how to" and not all the theory of "why".