i would ask him to view source to make sure it's printing the meta refresh url accurately. might want to try a value of 1 second instead of 0 too. the code looks good.
alternatively, if he doesn't want this handler page to show at all, .. he could do whatever he needs to, then call a header redirect with php.
PHP Code:
<?
// do whatever php logic here.
// don't print anything to the screen before this command
// since it is a header command.
header("location: " . $HTTP_REFERER);
exit;
?>