If this goes to court the defense will demand he produce his records for the following day’s activities- if he was scheduled for brain surgery (unlikely) that would be different than if he had office hours at a clinic with other staff.
He’ll be in court alright. It will be a case of failure to follow orders of a law enforcement agent.
What he has planned has no bearing or consideration on the part of United. It’s unfortunate, but it’s not United’s fault. They overbooked the flight, but that happens. Sometimes you have to get crew somewhere so that they can work a flight. You can’t drive them per union contract policy. Sucks but it’s the reality of it.