Book Chapters - Blank and backup blank too


I have been looking throughout the forum to help correct an error to my husbands book that he was almost finished.
He went in today and found that most of his chapters were blank and then the most recent ones are now all “special characters” (example __å4__æ4__ç4__è4__é4__ê4__ë4__ì4__í4).
He has been using Scrivener software without error for a year, and has everything on a thumb drive saved as his project “Eight”.
He is beside himself as that is the only place he saves his work and so very careful when saving to make sure that the internet is not on, and that the thumb drive is ejected correctly.

He goes into it today to find it’s all in a mess. There is an error that comes up that says “Could not load Amala etc” RTF : Reader Failed loading document F:/Eight.scriv/Files/Docs/84.rtf. Error: Ummatched in Rich Text File

I know that there are instructions below that error, however I am not understanding exactly what needs to be done. I also checked the backup files and there are 5 in the folder, that have 123KB and higher, so I did as the manual states and extracted them to the desktop and when I open the file by double clicking on it, the headings for each chapter are there, but everything is BLANK.

I am so willing to pay for services to get these chapters back, or if you can remotely log on to see how to fix this, I would be so very grateful.

We’ve had a very tough year, and now this happens and there is no reason why as he hasn’t even had the internet on while writing, and then saves everything.

Please advise as you’re our last hope

Thank you
Scrivener screen shot of text gone wrong.pdf (339 KB)