PHP Over my head

I am using a child theme of DIVI themes. The parent theme returns the correct content but my child theme returns older content only. I’ve found the php file responsible for returning what was once working but hasn’t been working for about 3 months. My eyes are crossed trying to figure out what is wrong with this code, hoping someone here can help me with this.

<?php get_header(); 
//are we getting all sermon series parent posts or are we getting all subposts of a sermon series?
$post_parent_qry = get_query_var( 'post_parent', 0 );
if ($post_parent_qry == 0) {
	$args = array('post_type' => 'message', 'post_parent' => (int) $post_parent_qry, 'posts_per_page'=>'20','order' => 'DESC');
} else {
	$args = array('post_type' => 'message', 'post_parent' => (int) $post_parent_qry, 'posts_per_page'=>'20','order' => 'ASC');
}
query_posts($args);
?>

<div id="main-content">
	<div class="container">
		<div id="content-area" class="clearfix">
			<div id="left-area">
		<?php
			//dcrosbie show parent post info
				if ((int) $post_parent_qry > 0) {
					echo "<h1>Sermon Series: " . get_the_title ((int) $post_parent_qry) . "</h1>";
					echo get_the_post_thumbnail( (int) $post_parent_qry, 'full' );
					echo "<p style='margin:30px'>" . get_post_field('post_content', (int) $post_parent_qry) . "</p>";
					echo "<hr/>";
				}
				
			if ( have_posts() ) :
				while ( have_posts() ) : the_post();
					$post_format = et_pb_post_format(); 
					$post_parent_id = wp_get_post_parent_id( $post_ID );
				
					if ($post_parent_id == 0) {
						//displaying sermon series parent posts
						$the_post_link = get_site_url() . "/message/?post_parent=" . get_the_ID();
						
					} else {
						//display subposts or a parent sermon series
						$the_post_link = get_permalink();
						
					}
					?>

					<article id="post-<?php the_ID(); ?>" <?php post_class( 'et_pb_post' ); ?>>

				<?php
					$thumb = '';

					$width = (int) apply_filters( 'et_pb_index_blog_image_width', 1080 );

					$height = (int) apply_filters( 'et_pb_index_blog_image_height', 675 );
					$classtext = 'et_pb_post_main_image';
					$titletext = get_the_title();
					$thumbnail = get_thumbnail( $width, $height, $classtext, $titletext, $titletext, false, 'Blogimage' );
					$thumb = $thumbnail["thumb"];

					et_divi_post_format_content();

					if ( ! in_array( $post_format, array( 'link', 'audio', 'quote' ) ) ) {
						if ( 'video' === $post_format && false !== ( $first_video = et_get_first_video() ) ) :
							printf(
								'<div class="et_main_video_container">
									%1$s
								</div>',
								$first_video
							);
						elseif ( ! in_array( $post_format, array( 'gallery' ) ) && 'on' === et_get_option( 'divi_thumbnails_index', 'on' ) && '' !== $thumb ) : ?>
							<a href="<?php echo $the_post_link ?>">
								<?php print_thumbnail( $thumb, $thumbnail["use_timthumb"], $titletext, $width, $height ); ?>
							</a>
					<?php
						elseif ( 'gallery' === $post_format ) :
							et_pb_gallery_images();
						endif;
					} ?>

				<?php if ( ! in_array( $post_format, array( 'link', 'audio', 'quote' ) ) ) : ?>
					<?php if ( ! in_array( $post_format, array( 'link', 'audio' ) ) ) : ?>
						<h2 class="entry-title"><a href="<?php echo $the_post_link  ?>"><?php the_title(); ?></a></h2>
					<?php endif; ?>

					<?php
						et_divi_post_meta();

						if ( $post_parent_id == 0 ) {
							the_content();
						} else {
							truncate_post( 270 );
						}
					?>
				<?php endif; ?>

					</article> <!-- .et_pb_post -->
			<?php
					endwhile;

					if ( function_exists( 'wp_pagenavi' ) )
						wp_pagenavi();
					else
						get_template_part( 'includes/navigation', 'index' );
				else :
					get_template_part( 'includes/no-results', 'index' );
				endif;
			?>
			</div> <!-- #left-area -->

			<?php  dynamic_sidebar('sermon-sidebar'); ?>
		</div> <!-- #content-area -->
	</div> <!-- .container -->
</div> <!-- #main-content -->

<?php get_footer(); ?>

The page I need help with: [log in to see the link]