My clients lack content (or it’s sub-par), do you have a wide-range of content I can use?
In my experience, yes, this course provides it, because the people whose books that I write for them provide quality information. I will usually sit down with my clients and determine what they want to share about their expertise, come up with the questions they need to be able to answer for somebody to impart that information, and then just do an interview with them where I ask them the list of questions we come up with and record that interview, and then use the transcription to create their books. If somebody wants to write a book to promote themselves, they should know enough to be able to provide content for their own book.
Since you seem to have some folks that don't seem to be able to articulate that information, then in terms of niche-specific content, then no, this course doesn't provide it (unless of course the person is in the publishing industry, but I doubt that's the case.)
I know that some of John & Jay's other courses offered PLR content as research material (especially a few years ago before PLR would cause your book to be removed from Amazon) so you could probably find some PLR on your subject matter if you really needed to. A couple of good resources are TradeBit and PLR.me if you want to go that route, but my recommendation is to find out the industry knowledge from your clients.