Delete A User

  if ($user_id == wp_get_current_user())
  {
    //Log the user out
    wp_logout();

    //Delete their account
    if (!current_user_can('administrator'))   //Don't accidentally delete our admin account!
    {
      require_once(ABSPATH.'wp-admin/includes/user.php');    //THis may be required to avoid "Fatal error: Uncaught Error: Call to undefined function wp_delete_user()"
      wp_delete_user($user_id);
    }

    wp_redirect( home_url( '/' ) );
    die;
  }

User Deleted Hook

//***************************************
//***************************************
//********** USER DELETED HOOK **********
//***************************************
//***************************************
add_action( 'delete_user', 'my_delete_user' );
function my_delete_user($user_id)
{
  

}

Running before other delete_user hooks

add_action( 'delete_user', 'my_delete_user', 1 );     //Priority 1, we need to run before ##### deletes user from its tables (default priority is 10)