Show all parents and children in custom post type in right order

Question

I would like to show all posts from a custom post type on one page with the ordering exactly like in the backend. I get the right ordering with wp_list_pages, but of course without the content.

1. parent

   1.1-> sibling

   1.2-> sibling

2. parent

   2.2-> sibling...

etc.

But I cant figure out how to set the order correctly with orderby.

Here is my code

    $args = array(
    'depth' => '0',
    'post_type'         => 'manual_documentation',
    'post_stauts'   => 'publish',
    'orderby'    => 'parent menu_order',
    'posts_per_page' => 10
    );

    $loop = new WP_Query( $args );
    while ( $loop->have_posts() ) : $loop->the_post();

    echo '<h1>';
    the_title();
    echo '</h1>';
    echo '<div class="entry-content">';
    the_content();
    echo '</div>';
    endwhile;

The result:

1. Parent

2. Parent

   Sibling Sibling Sibling

Does anybody know how to solve this problem? Thanks!