Does he already have a character on the destination server and is on an entry sub by chance? (Alternatively, has 8 characters on the destination server & is on standard sub?)

Since entry subs only allow 1 character per world, if he has an alt or character already sitting on the destination, it would disqualify the world from appearing in the list I'd imagine. A bit of a niche scenario, but thought I'd bring it up since its sort of a weird case.