Find all author's posts, including custom post types

allows an administrator to call up all of the posts created by a specific author

— where will they need to “call up all the posts?”

In any case, you’ll probably need to create a new WP_Query and specify the author and post type:

$author_args = array(
	'author_name' => 'my_author_name',
	'post_status' => 'any',
	'post_type' => 'any'
);
$author_query = new WP_Query($author_args);

// display results from $author_query
if ( $author_query->have_posts() ) :
	while ( $author_query->have_posts() ) : $author_query->the_post();
		// custom markup goes here
		// calling the_post() lets us use WP template tags like the_title()
	endwhile;
else :
	// no posts found, maybe display an error message?
endif;
wp_reset_postdata();