I think part of the issue you have there is it would be a really, really difficult book to put together, given the definition I have seen suggests a very generous carb allowance at the upper end of low carb. One mans low carb is another's carb-fest.
Similarly, for some, say on 30gr a day, a meal containing 20gr might seem highish, but doable, but for someone else, they might prefer an even spread of carb throughout the day, or, as many people are most insulin resistant first thing, they may feel better stepping up the carbs through the day.
I'm assuming your folks want to try this way of eating, or are you preparing them for when you go there?
Either way, in your shoes, I might be inclined to accumulate a portfolio of recipes myself, bearing in mind what they enjoy eating, and put them into a ring binder, or print out booklet style. The resource can be readily updated as your knowledge increases, and you discover new foods and experiences. Obvious starters might include cottage pie, with celeriac or swede mash, or cauliflower cheese, or crustless quiches.
As you probably know, there are loads of recipes on this site already. When my OH and I started down this route, we just kept eating (mainly!!) the same meals we used to, but swapped out the major root veg and other heavy carbs where we could. Obviously that changes some meals a bit, but needs must, and it's astonishing how I can honestly say I'm not bothered if a curry has rice riding shotgun with it, or not. Having curry alone (maybe with side dishes), is an excellent excuse for the glutton in me to eat more curry. There's more room on both my plate and in my belly!!
