Buresh Of Krakovitz bug

[Calculus]

So, after dealing with his cronies he just stands there, i can't talk with him, if i attack him he is immortal and, i can pickpocket letters, but they dont progress quest... so what am i supposed to do with him, was he expected to run away?


@edit:
I got him to surrender, i need to make him hostile then after returning to his normal state he will be surrendering and i can talk with him