If using the Wordpress author template to show user posts, change the main query via the pre_get_posts filter hook to show all types of posts by the author.

functions.php

<?php
function lstreng_author_any_post_types $query ) {
    // apply changes only for author archive page
    if ( ! is_author() || ! $query->is_main_query() )
        return;

    $query->set('post_type', 'any');
}
add_action( 'pre_get_posts', 'lstreng_author_any_post_types' );