The SHPEdit help file is Fred Chandla's work not ours, so not supported by us, really.
If the help file is not in the windows 10 format then there may be 3rd party tools that read the old windows help file format out there?
To get my old delphi help file format readable, I simply generated a VMware virtual machine with XP slapped onto it and then installed delphi and C++ builder on that. It also does the trick for playing Civilisation 4 as well
!
It may be that a simple solution like that would work for you, if you still have an old XP install CD kicking about in a drawer somewhere?