As much as no one wants to hear it, MJ and Dr. Murray are both at fault.
We don't know if the Dr. gave the last fatal dose or if MJ added to the Dr.'s dose. We just don't know.
We do know MJ was using propofol (among other things) to sleep, which is not the drugs intended purpose. We may hear MJ had some addiction issues to other sleep aids, we may not. We already heard about the demoral.
As far as who first started prescribing it and who continued, that would be different cases all together. Not this trial that is happening now, so it is best to keep the issues separate, while sadly the consequences were not.
As far as this Dr. goes, he knew this was an illegal, unethical, and potentially fatal plan. Any Dr. would. That is where any culpability on this Dr. comes in. He agreed to do this, knowing it could all go very wrong.
The jury will have to decide just what punishment the Dr. will receive. If they decide he gave the fatal dose, that is just one of the charges, the worst one. If they do not know who gave the fatal dose, but know the Dr. should never have gone along with the plan, that is a different charge, but does not include the death of the patient. Then there will, most likely, be testimony that the Dr. really did not know much about the patient and his addictions, and discovered it all too late. Which I would find hard to believe given the recording, he knew at least by May 9, plenty of time to stop administering propofol, get it out of the house, put it under lock and key, or just quit the job if his medical knowledge and intervention were being shoved aside.
It is a tough issue. I am looking forward to hearing the Court arguments and evidence. I would not want to be a juror on this case, not at all.