Bcc additional email addresses on all PMPro emails sent to the member.

bcc_on_member_email_headers.php

<?php
/*
 * Bcc additional email addresses on all PMPro emails sent to the member.
 */
function bcc_on_member_email_headers( $headers, $email ) {
    //bcc emails not already going to admin_email
    if ( $email->email != get_bloginfo( 'admin_email' ) ) {
        //add bcc
        $headers[] = "Bcc:" . "otheremail@domain.com,anotheremail@domain.com";
    } 
    return $headers;
}
add_filter( 'pmpro_email_headers', 'bcc_on_member_email_headers', 10, 2 );