Headmaster Temeritus Mulciber must've been informed by the castle wards that he had irate parents approaching. He waited for the Dolohovs to enter the Entrance Hall with a stoic expression, clearly resigned to what was sure to be an unpleasant encounter. A large part of his job was dealing with angry parents after all. One of the Death Eaters from Antonin's generation, not a lot upset Temeritus. Hermione found him to be a serious man, but dedicated to his position. With three children of his own who were still in the castle and one set to attend in the next few years, he took his job very seriously, more so even than previous Headmasters. Having his own children there upped the stakes for him, gave him even more of an incentive to make sure the thousand year old institution ran smoothly and safely.