After a bit of a marathon effort, I have finally restored my Grandfather’s email system to a working state. What a mess!
First thing I battled with was a corrupted PST file. scanpst.exe is a little hidden gem that helped with that.
Then, after someone “helped” 1, and messed up the mail delivery, I had to fix his outlook profile. Trouble was, I could not find the “show profiles” tab in the mail control applet. This was maddening, because it was turning up nothing in my Googling.
Turns out that somehow, outlook had been switched into “Internet Mail Only” mode, and I suppose this somehow removes the profile editing stuff. However, the profile that was left was so broken that it had to be fixed. 10 GOTO 10.
Lukily, I found this link which informed me about IMO mode, and how to switch it back. So a lesson for everyone is that in order to use profiles in Outlook, which you need in order to have multiple PST datafiles, and to control how and where mail is delivered, your Outlook must be in Corporate Workgroup mode.
May I also add that TeamViewer is a very good remote control solution, which I used to great effect today for about 3 hours, including 2 reboots.
 By “helped” I mean completely screw everything up.