Firstly, if you're opening the document
directly from your email, don't!
Save it to your hard drive first and then open it from there. That might be all that's needed. If not, go to where the file is stored on your hard drive and right-click on it. Select 'Properties' and look to see if 'Read only' is checked. If it is, remove the tick, click Apply and then OK.
If that doesn't help, go back to 'Properties' and look at the file type. You're hoping to see something like 'Microsoft Word 97-2003 Document (.doc)' but I suspect that the publisher has opened your father's manuscript in a more recent version of Word, then saved it using the default file format offered by that version (resulting in Word 2003 being unable to handle it properly).
If so, you can ask the publisher to re-open the file, select 'Save As' (NOT 'Save') and choose the 'Microsoft Word 97-2003' format.
Alternatively you can install an alternative Word processor, such as OpenOffice, which will be able to handle the newer file format:
https://www.openoffice.org/
(NB: If you install OpenOffice, I strongly recommend changing the default file format so that you don't end up with the publisher unable to read your father's manuscript! Easy instructions here:
http://helpdeskgeek.com/office-tips/set-openof%EF%AC%81ce-org-to-save-in-microsoft-of%EF%AC%81ce-format-by-default/ )