In Spider-Man: Homecoming (2017), they decided to modernise Flash by not making him a handsome jock and instead a smart, preppy bully to Peter to get away from that stereotype. Here's a picture of him standing next to Brad, a handsome jock, introduced in the next film as a rival to Peter... wait.
Patrick Bateman is pretending to talk to someone called John but it also sounds like he says Sean? So he could be pretending to be talking to his brother Sean Bateman from The Rules Of Attraction, another book by Brett Easton Ellis and the movie adaptation is named Fuck The Rules.
What about it?
There is also a deleted scene in Fuck The Rules where Patrick is played by someone else on a phone call