Medical training
Forget the levels of competence. Has the airline taken out insurance on the crew to pay for the times it doesn't always go as expected? Doctors in the air think twice about offering their services because of the malpractice issue. Who will support the crew if they jump in to help and, for a variety of medical reasons, are unable to offer the complete care needed? With everyone and his first cousin ready to sue for any adversity, even self-induced, it woud be a foolhardy crew member to offer medical intervention, regardless of his/her training.