First of all if he did a complete format using Windows Vista or Windows 7, then that's unrecoverable. However, the complete format of an 1TB external drive would take some couple of hours, unlikely you just sat there and watched (two passes in a row).
In case there was a complete format, the data recovery programs would bring back no data at all. If they all recover different pieces of data, you should keep trying. Different programs use different approaches and get somewhat different results on a quickformatted drive.