The riched32.dll is on his machine in 4 places.
Trying to use reg server to register it fails each time with:

The module "riched32.dll" was loaded but the entry-point DllRegisterServer was not found. Make sure it is a valid DLL or OOCX file and then try again.

I have looked online but a lot of articles want to update the DLL and "Download it here" which I am very aware of. He was going to try to fix the TypeLib param in the registry as well as try an SFC scan.