Yes you can awaken him I'm just not sure how. Was in the castle one day and there he was awake and wasting people. After he had killed a few my group engaged him. We damn near killed him and as a shammy if i knew what i know now about my spells we could have. Alas we died and he returned to his perch and became as stone again.
We waited around, someone thought that he became attackable at a certain time of day, but we never saw it.
So still don't know how to get at him.