I totally missed that evil-billionaire David was David-still-possessed by Farouk.
Not only possessed, but having lost or surrendered the battle, so Farouk was now in control. I think what tipped me off (aside from the brief shot of Rich Creep David looking at Farouk) was when he telepathically attacked Amy and gave her a nosebleed. If any of David were still in there, he'd never have hurt his sister.