How get current menu childrens from main menu?

Hello!

I have a problem. I can’t find solution for my target.
I need get current menu children list.

Example:

-Parent 1
–Child A
–Child B
–Child C
-Parent 2
–Child B
–Child C

All children’s parent is Parent 1 (but not Parent 2).
But in navigation I have grouped the products.
When I go to “Parent 1” or “Parent 2” page, then in the page generated the list of products (children’s pages).

First solution I write where get the page children:

<?php
        $mypages = get_pages( array( 'child_of' => $post->ID, 'sort_column' => 'post_date', 'sort_order' => 'desc', 'post_status' => 'publish' ) );

        foreach( $mypages as $page ) {
            $content = apply_filters( 'the_content', $page->post_content);
            if ( ! $content ){ // Check for empty page
                continue;
            }
    ?>
    <figure class="img_with_caption category_caption">
        <?php
            $img_src = get_post_image();
            if(!empty($img_src)){
        ?>
        <a href="<?php echo get_page_link( $page->ID ); ?>">
            <img class="alignleft category_img" src="<?php echo $img_src; ?>" alt="<?php echo get_page_link( $page->ID ); ?>" />
        </a>
            <?php } ?>
        <figcaption>
            <h3><?php echo $page->post_title; ?></h3>
            <p><?php
            $str1 = substr($content, strpos($content, '</figure>')+9);
            $content_fragment = substr($str1, 0, strpos($str1, '.')+1);
                    echo $content_fragment;
               ?></p>
            <p><a href="<?php echo get_page_link( $page->ID ); ?>">
                <?php
                    $lang = qtranxf_getLanguage();
                    $caption = get_content_data();
                    echo $caption[$lang]["read-more"];
                ?></a></p>
        </figcaption>
    </figure>
    <?php
        }
?>

And its working fine, but I can’t grouped the products.
I need get all this via menu navigation, but not via page relationship.

I all day searching how write the solution, bet can’t find.
Only this code I get:

$current_terms = get_queried_object();
    $locations = get_nav_menu_locations();
    $menu = wp_get_nav_menu_object( $locations[ 'health' ] );
    $menu_items = wp_get_nav_menu_items( $menu->term_id, array( 'post_parent' => $current_terms->ID ) );
    if( !empty( $menu_items ) ) {
        echo '<ul>';
        foreach( $menu_items as $menu_item ) {
            echo '<li><a href="' . $menu_item->url . '">' . $menu_item->title . '</a></li>';
        }
        echo '</ul>';
    }

But
wp_get_nav_menu_items( $menu->term_id, array( 'post_parent' => $current_terms->ID ) );
this function working only in “Parent 1” page and show relationship children, AND dublicate, because the same children’s is in “Parent 2”.

But on Parent 2 page not showing.

Please help me some one.
Thank you.