Help strings are supported on MS-Windows and MS-DOS as well.

Mouse highlight is supported on MS-DOS.

etc/NEWS

@@ -191,8 +191,12 @@ all frames except the selected one.
 to the source name (.emacs.el), if that exists, after loading it.
 
 ** The help string specified for a menu-item whose definition contains
-the property `:help HELP' is now displayed under X either in the echo
-area or with tooltips.
+the property `:help HELP' is now displayed under X, on MS-Windows, and
+MS-DOS, either in the echo area or with tooltips.  Many standard menus
+displayed by Emacs now have help strings.
+
+** Highlighting of mouse-sensitive regions is now supported in the
+MS-DOS version of Emacs.
 
 ** New user option `read-mail-command' specifies a command to use to
 read mail from the menu etc.