If he was flying the ILS to 30, he was way off-course. Islamabad has SSR and they do a very good job vectoring you. ATC would have warned him. Maybe he ignored them. That's what you are inclined to do if you have 30,000 hours.
Spatial disorientation, loss of situational awareness, complacency, over-confidence? Take your pick. The first two have become chillingly commonplace recently.
I would also imagine that if he was flying the DME arc to 12 that he was flying manually and we have heard a lot about loss of flying skills because of the over-reliance on automation. Maybe he stalled her.
Too bad we have no tradition of disclosure of air accidents. The ATC tapes, the DFDR and CVR will be quickly sealed and the public fed BS and left to speculate. We will never know. No lessons learnt so we are doomed to repeat them.
'A doctor buries his mistake. A pilot is buried with his.'