Not in an N reg aircraft hopefully
FL120 is legal (FAA); FL140 would not be after 30 mins. He was a passenger anyway.
For me, any airways departure is a
no-go unless I have enough oxygen to complete the flight at either FL160 or at the planned level, whichever is higher. This has caused me to waste a whole day looking after a bottle refill at Crete last year (being sent from a scuba shop to x to y to z and eventually ending up in an industrial gas factory) but I would never change this rule.