Being a shaman king, Yang Kai might even be able to save the old patriarch, but he could never be sure if it was a final cure or if the demon spirit was still lingering someone deep within the old patriarch mind or body. It's too risky. Especially since the old patriarch is an array master, so under the demons' influence, he would be able to crack the seals again, if given a chance, even a century later when folk's attention had become more lax.