On 09/11/19 1:32 AM, tim Rowledge wrote:
> Having never - to the best of my knowledge - used anything that edits
> LaTEX, I am ignorant of what tool I might use to make any attempt at
> helping. What editors (Mac, obviously) are capable of editing such a
> document in any form other than the 'good grief what is this stuff'
> plain text?

There are a whole bunch of GUI editors for TeX on MAC:

  TeXMaker, TeXstudio, LyX, MacTeX, TeXShop, MikTeX, ...

The TeX User Group (http://tug.org/begin.html) has a FAQ on MAC at 
https://texfaq.org/FAQ-sysmac

vim also has a latex-suite to ease editing TeX.

HTH .. Subbu