I have never asked a therapist that question. From what I have read, therapists take it very hard. I read about a CBT therapist and author (I don't recall which one) who had to console himself with thoughts that he had honestly tried his personal best, feeling grief and self-doubt was perfectly human, and that the best approach was to learn what he could do better in future situations with potentially suicidal clients. "Grieve and grow" is all a person can do in that situation.