Recently in WordPress I needed to create a navigation that would display a page’s parent page and all of that pages children, I am a bit rusty with PHP but here is what I got to work.
If you need to order the posts by the order value change the
$pages = Line to
$pages = get_pages('child_of='.$pageLinkID.', 'sort_column' => 'menu_order', 'sort_order' => 'asc');