This is one of the many problems caused by the Microsoft Works Suite Add-in
for Word. If your friend is running Word freestanding (not starting it from
the Works Task Launcher), then he should uninstall the add-in (through
Control Panel | Add/Remove Programs). This will not uninstall Works or Word,
just the add-in that allows Word to be started from Works and adds some
other functionality that he is unlikely to want to use (such as using a
Works database or address book as the data source for a mail merge in Word).

After the add-in has been uninstalled, open Tools | Customize and use the
mouse to drag all the excess Mail Merge entries off the menu.

--
Suzanne S. Barnhill
Microsoft MVP (Word)