... I can't convert all the multiple spaces to a single space then set tabs because there are single spaces that I want to leave unchanged. ...
Yep, that's why I always use an intermediary symbol. Above I said to use the "*", but of course if that is used elsewhere within the text you can use anything else that is unique instead. Often if I don't know every symbol within the text, so I use a longer combination as the replacement, e.g. "*+*" or "*-*+*-*" or "{tabhere}" - anything which is highly unlikely to be used elsewhere.
Above I also said they were spaces (and in your picture they do looke like sapces) since that is the usual novice approach to columns, but in some cases a novice user will use tabs, but not custom tab stops, which often results in multiple tabs between neighbouring columns on some lines. The above process will still work by replacing the double-tabs with the unique symbol.
edit - I replaced "5 spaces" with a "*" but that doesnt work because there are other places with "5 spaces"....know what I mean?
There shouldn't really be any need to have even double-spaces, let alone five spaces, but you could copy the parts that do need changing to a new document and make the Find-Replace changes there.
Another way is that in Word and InDesign, the Find-Replace can work on only the selected section of text - so ON A BACKUP OF THE FILE you can select a section of text, perform the Find-Replace, select another section, perform the Find-Replace, etc. It's tiresome, but works.
In Word (except the current version, I think) you could set up a macro to perform the multiple Find-Replace steps so all you have to do is run it each time. In Word or InDesign you might be able to use AppleScript / Automator to make it the process a bit quicker. Either way you'll still have to manually select each section and then run the macro / script.
If it is an on-going task, then a better option might be to teach the person sending the file how to do tabs properly.
