It would be nice to think that even if he had made it onto the plane, the captain would have noticed his state and stood him down. But of course he did not get that far, so we will never know.
I remember an English TV
documentary of a few years back that showed an overnighting crew getting legless and returning to the hotel only a few hours before they were due to turn up for duty. Apparently the captain "slept it off" on the return to the UK, leaving the only slightly less hungover FO to fly back, not good at all.
In this case his excuse that he was going to tell the captain he was sick and not going to fly does not add up though. Especially given that he was in uniform and trying to access airside through the crew channel. If he was "sick" why could he not use the phone. Of course maybe he was so legless he did not think of that.
Quick question though. Would the flight have been able to leave with just the two existing crew? Or do they need the relief staffer?