Extending EmailTemplates to add Cases Module in Sugar 7.9.5, Parsing Email not working

I was able to add the case modules variables in the email template Reference Insert Opportunity variables into Email Templates ) , I'm not able to parse the emails,

I did try overriding function email2Send in modules/Emails/Email.php .   

in custom/modules/Emails/customEmail.php

require_once ('modules/Emails/Email.php');

   class CustomEmail extends Email {

      function email2Send($request) {

         /* added $_REQUEST['parent_type'] == 'Cases' */

   }

}

But its still not parsing the values

Any help is appreciated