This is an old trick of his that he picked up and dusted off again. He sent one to Mary for $900, ostensibly to cover all the royalties he didn’t make from books he didn’t sell. Since he used to routinely send people phony bills for thousands of dollars for pissing him off, it would seem he’s trying to keep his fraud below a certain dollar amount, so the Feds don’t get involved.
Over the years, so many people have reported him to PayPal that I wonder whether there’s a magic number of complaints that have to be lodged before PayPal does anything about it. By all rights, he should have lost his account by now, or had it frozen.