Delete attachment when question/answer is deleted

At the moment, you can add the following code to the functions.php file to delete the attachment when a question is deleted.

function delete_post_children($post_id) {
  global $wpdb;
  if ( get_post_type( $post_id ) == 'dwqa-question' ) {
    $ids = $wpdb->get_col("SELECT ID FROM {$wpdb->posts} WHERE post_parent = $post_id AND post_type = 'attachment'");
    foreach ( $ids as $id ) {
        wp_delete_attachment($id, true);
    }
  }
}
add_action('before_delete_post', 'delete_post_children');

However, you only possible manual delete attachment for the answer.
We will check and discuss about this option.