/* $this->order = MagentoSalesModelOrder */
/* Get Total numbers of delivered items */
$customerEmail = 'abc@test.com';
    $ordercollection  = $this->order->getCollection()
        ->addAttributeToFilter('customer_email', $customerEmail);
    $totaldelivereditems = 0;
    foreach ($ordercollection as $orderobj){
        foreach ($orderobj->getAllVisibleItems() as $item) {
            $totaldelivereditems += $item->getQtyShipped();
        }
    }