Displaying custom posts in categories

To retrieve all the terms attached to your taxonomy “brochure_categories”, you can use get_terms() function. More info here.

Once you’ve got your terms, you can traverse them and query your custom posts with:

$query = new WP_Query( array(
  'post_type'             => 'brochures',
  'brochure_categories'   => $current_category,
  'posts_per_page'        => -1,
  'order'                 => 'ASC',
  'orderby'               => 'title',
) );

You can now display them, by category, as it suits you.

Is it ok for you ?