I played through most of IWD and then decided to play HOW.But when i came back to IWD and the last boss in Easthaven.I send 2 fighters after 1 golem and the other thing.And another after the other golem and so Poquelin attacks the fighter on his own i cast otilukes sphere take out the golems and other creatures.Then I summon 2 shambling mounds to distract poquelin.Then I attack him with all my fighters taking him to almost dead but he won't die he just keeps casting that flame thing and teleporting away not bothering to attack me and he on't die he stays on almost dead.It's not that i'm not strong enough he was on almost dead for 10 mins literally.Does anyone know how to fix this?If so please tell me.

I had that bug happen too. The way i fixed it, was by casting an instant death spell, like power word : kill. It did the trick for me.