Using page slug in wp_query

pagename is for request page (core page post type) by slug. What you want, if I understood correctly, is to get “attorney” posts that belongs to same case-log terms that current “case” post. I would do it something like this (not sure where you are going to execute the code, I’ve tried to code as universally as possible):

if( is_singular( "case" ) ) {

    //We are in single "case" view
    //Get the ID of current case post
    $case_id = get_queried_object_id();

    // Set "post_type" agument for the query
    $args = array(
         'post_type' => 'attorney'
    );

    //Get the terms from case-log taxonomy
    //get_the_terms returns an array of term objects, false or a WP_Error object
    $terms = get_the_terms( $case_id, 'case-log' );

    if( ! is_wp_error( $terms ) && $terms ) {

         $terms_ids = array();

         foreach( $terms as $term ) {
             $terms_ids[] = $term->term_id;
         }

         // Set "tax_query" agument for the query
         $args['tax_query'] = array(
             array(
                 'taxonomy' => 'case-log',
                 'terms'    => $terms_ids
             ),
         );

    }

    $case_attorney = new WP_Query( $args );

    if ( $case_attorney->have_posts() ) {

        while( $case_attorney->have_posts() ) {

            $case_attorney->the_post();
            ?>

            <div <?php post_class() ?>>
                <h2><?php the_title() ?></h2>
            </div>

            <?php

        }

        wp_reset_postdata();

    } else {

        echo "No matching attorney";

    }


 }