Maur still has Xander's spellbook and spell component pouch on him, so Phar would have to ask him for them. While there is still the question of Xander's guilt in working for the cultists, he did surrender in a traditional manner, so he's being treated better than Aries and Eike.
Still, all of his possessions are considered forfeit if the PCs choose to claim them. And he has already given over his personal wealth and a scroll with two fire trap spells on it. Aureus has the duergar's gems and gold on her (but she has not claimed them as her own). She handed over the scroll to Phar while they were coming back to Carnell on the launch.