show list of latest comments for each post in a loop

You should place your code inside the loop and add to the args array 'post_id' => get_the_ID() so it should look like this:

while(have_posts()){
   the_post();
   //your post loop output
   $args = array(
    'status' => 'approved',
    'number' => '5',
    'post_id' => get_the_ID()
    );
    $comments = get_comments($args);
    foreach($comments as $comment) :
        echo( $comment->get_avatar . $comment->comment_author . '<br />' . $comment->comment_content);
    endforeach;
}