function set_posts_per_page_for_attorneys_cpt( $atty ) {
  if ( !is_admin() && $atty->is_main_query() && is_post_type_archive( 'attorneys' ) ) {
    $atty->set( 'posts_per_page', '-1' );
    $atty->set( 'meta_key', 'last_name' );
    $atty->set( 'orderby', 'meta_value' );
    $atty->set( 'order', 'ASC' );
    $atty->set( 'facetwp', true);
  }
}
add_action( 'pre_get_posts', 'set_posts_per_page_for_attorneys_cpt' );