form submit handler is not called
After careful rereading of the user module, i realize that 2 more hidden form values need to be added so  the same delete_multiple_server_confirm_form will get called again after confirming action,otherwise the display_server_form will be rendered.

$form['table'] = array('#prefix' =&gt; '&lt;ul&gt;', '#suffix' =&gt; '&lt;/ul&gt;', '#tree' =&gt; TRUE);
$form['operation'] = array('#type' =&gt; 'hidden', '#value' =&gt; 'delete');

 foreach($servers as $id) {


    $form['table'][$id] = array(
         '#type' =&gt; 'hidden',
         '#value' =&gt; $id,
         );
   }