Just to clarify, the Air Canada pilot charged was a First Officer. Just one of the many facts the media got wrong.
This flight is normally scheduled with a Captain, First officer, and Relief Pilot, but on this day there was one Captain and two First Officers. (When this crew left Canada, there was no Relief Pilot available so a First Officer was substituted instead.)
When the First Officer had to leave the aircraft, the "augment" First Officer took his place. The additional pilot was a contract requirement, and not required by Canadian Air Regs, so they operated home with only a Captain and First Officer.
There was little or no inconvenience to the passengers. I doubt they even knew that there was an incident because the pilot left the aircraft on his own.
(I was told that after the initial breath test in the flight deck, the police left the aircraft and instructed the pilot to meet them in an area outside the aircraft)