Hello! I have the same issue. I chose to let him live but I regret my kindness!
Lohar wanted a proof of his death so I came back in the cave, but he refused to talk to my main and a companion, so I tried to kill him but he's stuck at 0 hp O armour with his bone cage and keeps saying bad words to me.
I finally could talk to him with one of my other companions and he suggested I gave him presents to show my good will: I gave him stuff and money so that his attitude towards this companion goes up to a positive one but now he remains silent, can't talk to him with neither of my 4 characters...
Did you finally find a clue?
