So I'm at the part in the Pitt where you get to meet Ashur in Haven and I walk up, like you do to talk to him and his legs were shaking. No big deal, but I can't talk to him and he doesn't respond to the Talk (X) command. I decide that maybe I could shoot Krenshaw and a few raiders to make him move.
I hole up to the left by Ashur's room and zoom in on Krenshaw's head and fire a round with the Gauss Rifle and Ashur falls down! The best part is, he stayed fallen down for 5 minutes.