Definitely don't do it!
Think about it: Why, just why, would a client want the Word version of a risk assessment report?
Yeah, that's right - so they can rip off your IP and do future updates themselves without calling on your "expertise".
It's very similar to when people register for an event and then say "sorry I can't come but can you send me the powerpoints?" You just know they're bunking off work, collecting the IP, and skim reading the content in case anyone asks about it.
Here's another example: It's also like when a prospective client asks if you can send them a "sample strategy report" - in Word format! Yeah right, just so they know what it looks like. Not at all so that they can rip it off.
Trust your instinct on this one. There are plenty of mickey-takers out there. Of course, in your situation, said client will say that he just wants to copy chunks of it into another document. Which of course is only a tenth of the truth.
I'd just go cold on his e-mails. Especially if there's not much of a relationship there anyway and you doubt they're going to give you more work. He's a mickey taker, he knows it, and you know it.
Or alternatively perhaps just spin him some bull about "Sorry we can only give out the PDF versions because of our company policy which is very strict about security and we have to send PDF versions only in order to ensure that document metadata is not accidentally issued to clients"