Try this:
$args = array(
'sort_order' => 'asc',
'sort_column' => 'menu_order',
'hierarchical' => 1,
'parent' => $post->ID
);
$pages = get_pages($args);
Try this:
$args = array(
'sort_order' => 'asc',
'sort_column' => 'menu_order',
'hierarchical' => 1,
'parent' => $post->ID
);
$pages = get_pages($args);