Pat's "writing" technique fucking sucks.
He's already admitted that he doesn't know how the plot will end when he starts writing a story. That in itself is bad enough for any novel, but this is someone who writes whodunnits - the whole point of a well-written whodunnit is that the clues to the killer are scattered throughout the story, and you can piece it together yourself if you're clever enough. You pit your wits against the protagonist, because you both have access to the same evidence. If the author themselves doesn't know how the killer did it when starting out, how are you supposed to do that? You end up with writing like Sherlock, where the protagonist is basically a wizard and the audience have no way of guessing how the crime was done because the protagonist just pulls new information out of their backside to solve the case. Sherlock is a prime example of a smart character written by someone who isn't smart. That's why good authors are rare, because you have to be as smart as your characters to write them convincingly.
So it's telling that he's given up on whodunnits (in spaaaaace) to do stupid meme fanfiction on characters that a much smarter person wrote that are conveniently in the public domain. Dickens did the thinking for him 150 years ago. Likewise, Sherlock is another good parallel because Arthur Conan Doyle was a very clever man who wrote a character who was also a very clever man, so that by writing Sherlock Holmes fanfiction you can take advantage of the fact that the audience already know the character's a genius without having to establish it yourself. This is why bad writers like Pat are drawn to fanfiction, because someone smarter than you already did most of the legwork.
It's also telling that he's writing to the word limit. Good authors either write as much as their plot demands and however long that requires to write is however long the book ends up being (notably the Harry Potter books vary in length quite a bit because Rowling writes to the plot, likewise with Stephen King), or you get experienced enough that you know how much plot you need for a certain length of book and plan accordingly. Pat, on the other hand, is taking his plot by the seat of his pants (because he hasn't planned it out in advance) and is just writing ... stuff ... until he reaches an arbitrary word limit. It's fitting that he's writing fanfiction because that's what a lot of fanfiction authors do. Vomit words onto the page until they reach a big impressive number, then the plot can stop.
And finally it's most telling of all that Pat is talking as if his work is nearly done. He was even planning to release it in time for Christmas at one stage. For a competent author, getting to the end of the plot is the end of stage one, the first draft. For many authors, that's the easy part, sometimes the part that takes the least amount of time. I can shit out 1000 words an hour of words on a page, that's really fucking easy. What's hard is then going back over it and editing and redrafting it until it's actually good. You check for typos, you check for continuity errors, you check for plot holes, in a story like a whodunnit you check for the amount that has been revealed to the reader. Is it too easy to guess whodiddit? Too hard? Even in other kinds of story, you need to come in afresh and put yourself in the mind of a first-time reader and assess whether the story makes sense to them and whether it has the required intellectual and emotional impact. That's very hard given that you've been inside the story, not outside it, and often that process requires an external editor to do properly.
The first draft is the most enjoyable part of writing, but that's all Pat wants to do. That makes him a hobbyist, not a professional. He's borrowing other people's characters, he's not structured the plot ahead of time, he's writing to the word limit, and he thinks the work is ready to publish as soon as he gets there. Without reading a single word of this book I can tell it's going to be fucking terrible because of how amateurish and lazy the author's process is.
He should stick to spiced sausage manufacture.
