To do a double-check - I looked in my up-to-date Win10 x64 v1809 system, where I was told that 'OS is not configured to support MSOffice2010', so I deleted \Program Files(86)\MSOffice2010\, and re-installed it. When I clicked on '?' in Excel, the right window opened containing the expected text. So while what you say may be true, MS did NOT prevent HELP from working in this other system.
I understand that there is a REPAIR option in RUN ....wiz.cpl - I have lost the precise description and SEARCH has not found it for me.
I have discovered a standalone Microsoft Support and Recovery Assistant for Office 365 (SaRA) that does not require Office 365 - have not yet had a chance to test it.