I don't take issue with his desire to make it so long, but a first-time author will have trouble finding a publisher who is willing to offer an advance for such a large book. I think most agents would see the size of it and drop it in the recycle bin without reading past the title. If he was an established author with a following, he'd get some consideration, sure. I almost wish he'd managed to reach an agreement with a publisher. Imagine what a horror show that would've been!
But that's why I'm glad that there are options for self-publishing now. Everything from a massive memoir to a short booklet can be put up for sale. And if you are savvy enough at marketing, you can do quite well even without massive sales, since most of the earnings go to the author and not to a publishing company. If his books are making money, good for him! And if it saved a publisher, editor, or agent the grief of having to deal with him, the world is a slightly better place overall.