Tony watched Abby from the doorway for a few minutes. He had no idea what to say to her. He knew nothing would make it better, that much was obvious. When Kate had died, he'd just hugged her. It was all he'd been able to offer in his own grief. It was easy to forget that was a long time ago for Abby, when it had happened so recently for him. He still felt the ache of losing Kate every day. Ziva being killed didn't have the same impact for him. He really didn't know her that well yet. But that didn't change the knowledge that she was his partner, and she was dead. And that just made him angry.
It was only the knowledge that Abby needed him that kept him in this room, from going out there and finding that demon. Abby had just lost the person she'd had here who knew everything that had happened over the last few years. In Tony's world, he knew Abby better than Ziva did. In Abby's world, he figured that wasn't the case any more.
When she started crying anew, he moved over to the couch and sat beside her, wordlessly slipping an arm around her shoulders, pulling her closer to his side.
"I'm sorry, Abs." If he could change it for her he would.