|mmm Thumb drives/flash drive/usb sticks (and SSD cards) are not the most secure or reliable for storage; unless one has another copy of the contents elsewhere... They are really meant to be portable, short term storage devices only.|
Unless one of the other regulars here can come up with a how to.. I suspect you are out of luck in recovering the files.
Meahwile I found this amongst other hits via a google trawl:
I used the search term/string:
word was unable to read this document. it may be corrupt
- and got a slew of hits including the one above... Perhaps repeat my google trawl and see if any of the hits work for you?