Looking for Recommendations for Someone in a Reading Slump

Hello there! I’m looking for a book recommendation for my friend who has been in a reading slump for a few years now. He’s got a gift card to a book store that he’s looking to spend. Here are some things we’re looking for:

-Popular fiction. Something that’s gripping and maybe a faster read.

-He’s a fan of mystery and horror but isn’t looking for a book in those genres specifically. It can definitely have elements of mystery and horror but they’re not the central genre.

-Doesn’t need to be a new novel but maybe not a classic piece of literature.

Thank you for your suggestions in advance! We have very different tastes so I haven’t been much help.