Thoughts on Kelly’s Death

Like many I blame Juliette for Kelly Burkhardt’s death, but could Nick have done anything to warn her? I don’t recall if he knew Juliette was metaphorically and possibly literally in bed with the Royals, but he at least knew she was a pissed off hexenbiest. It may not have occurred to him that Juliette would help set a trap for his own Mom. Thought? Opinions?