He employs a number of c0-writers and ghost writers.

I read an article that described his method as writing a draft outline of a book and then assigning it to one of a stable of co-writers. Some have been co-authored with established writers as well as relatively new writers.

His "Private" series of 13 books to date used 8 different co-authors, including Ashwin Singh.

He does this for adult as well as children's books.

Given the genre of most of his books--thrillers, humor, historical--it doesn't seem to matter if there is no detectable style to his writing.