Yes, it is fairly obvious that he wasn't innocent based on that quote.
The high-prescribers were people operating out of strip malls, often with unclear credentials, and whose main clientele were opioid addicts. Many of these people (I am choosing not to use the word doctors) ended up in prison...consultants who were advising them, not so much.
There are a large number of people who could do this job, it is reasonable to ask whether the person you want doing this job is someone who, at best, was unaware that these people were breaking the law. And, to be clear, he was Partner of their Healthcare practice whilst this was going on...he wasn't just making Powerpoints.
The revolving door between consultancies and government must continue. No-one is more skilled than running government than lawyers and consultants who have lots of experience in...advising other people how to run things.