He was still on duty and available.
Yes, but the duty was a non safety sensitive duty (Paxing) and therefore doesn't require testing. Had he then had a drink and been subsequently told he was to fly he would have had to reject the duty.
Interesting post by
tail wheel, in the company I work for you can never call someone drunk even if they clearly are, something to do with defamation. Instead you have to say they are unwell and if you kick them off the flight then they are too unwell to fly.
That being said if a crew member thinks you have had a drink, and the subsequent test is positive then you're either under the influence or having a REALLY unlucky day.