You could either write a script to generate the Word document, as there isn't any built-in way using Advanced HTML/PDF templates.
Or, you might be able to generate an MS Word XML format document using the HTML templates, saving it with a .doc extension so that Word will open it. See
https://en.wikipedia.org/wiki/Microsoft_Office_XML_formats for an example. Either way will be quite a bit of effort, and definitely not something NetSuite provides standard.