If you can give a few more details about the kind of projects your friend works on regularly there are likely a few Perl, as well as other, production solutions that will make their InDesign (and graphic design) experience a lot smoother.
For example: Are they designing books that will be printed and distributed digitally? While repetitive color separations and conversions from CMYK (and/or Pantone spot colors) to RGB may be best handled by AppleScript, the content for the book could be munged with Perl. Using a similar process to templating websites, book chapters, titles, footers, pull quotes etc. can all be broken apart and tagged (likely xml for InDesign). Your friend could then import all the separate chunks of content into an InDesign template with styles specified for every chapter using AppleScript.
An aside: If they are not already using a version control system for thier design files I would strongly encourage them to do so. Even though digital asset management was the buzz word in creative departments 5+ years ago, designers' hard drives are still filled with files like: BookDesign_v1, BookDesign_v2, FinalBookDesign, FINALBookDesign etc.
"...the adversities born of well-placed thoughts should be considered mercies rather than misfortunes." Don Quixote