You're downvoted, but I'm certain this is exactly what it is.
That trick doesn't work anymore for any reasonably modern email client.
That's when you remind him that your boss needs to get this role filled by the end of the week so if you don't get a response by tomorrow you'll have no choice but to offer the job to another candidate.
You can put it into a .zip archive or just send an email containing a link with a fake PDF
This sounds way too sophisticated for them to risk it with a "Offer.pdf.exe". Especially if it was state-backed. If the victim notices it, and the bar isn't high, you'd basically spook him away and alert the entire company.