preview cant open pdf file attached to a word document any

The key clause here is in the past. Preview is continuously changing, and I fail to see how it, or Quick Look could work on an PDF object embedded in a Word document. Worse, it would appear that this particular PDF may be linked to a remote server location, and cannot find the Adobe Acrobat solution to open it. Just guessing, because I have seen Word documents attached to PDF, but not PDF attached to Word documents.

I recommend that you share this question on the Microsoft Word answers community where they are all Word users on Mac. At that link, select your particular Office Product category (e.g. Office 365, Office 2019, etc.).

Are the PDF files embedded in the Word document or just attached along with the document?

Please read the following user tip and provide additional information on your system, app versions, email provider, etc: Writing an effective Apple Support Communities question

I never encountered a PDF marsupialized within a Word document in 30 years of computer industry experience. So, cannot fathom why someone would risk that folly, just because Word permits it via Object embedding.

Why would anyone embed PDF documents in a Word document?

That makes pretty much no sense at all.