How do i get all author posts on custom post type list

The author key/value query won’t work.
Try modifying the query by moving the query out of the meta query like so:

array(
    'author' => $author,
    'meta_query' => array(
        'relation' => 'OR',
         array(
             'key'       => 'leads_status',
             'value' => '-1',
         ),
         array(
             'key' => 'leads_status',
             'compare' => 'NOT EXISTS',
         )
    )
)