in actions for member/login
$this->getUser()->setParameter('username', $username);

in blocks/usebox components:
$this->member = MembersPeer::retrieveByPK($this->getUser()->getParameter('username'));

in _userBox.php
<h3>Welcome <?= $member->getName(); ?></h3>

and then i get:
Welcome 
Fatal error: Call to a member function getName() on a non-object in /home/admin/domains/3dkingdom.org/public_html/v6/apps/frontend/modules/blocks/templates/_userBox.php on line 2