This is so heart wrenching I can hardly stand it. Just keep telling yourself...it will get better, it will get better. Leslie, maybe your husband can assume some of the caretaking today, so you can have a break from the emotional truama of seeing Graham in pain. The only other thing I can suggest is to talk to your regular vet and see if he has any input into the situation.
Leslie, you are feeling the pain of Graham's pain and it is just as intense for you as it is for him. We are all praying that this phase will be over soon.

Is he eating anything? Keeping it down? How do you manage with getting him up and out to go to the bathroom?