at one time someone thought it would be good to have ''an airline within an airline'' to better compete with low cost carriers.
the airline within the airline did not offer oxygen service for routine medical situations.......ie on the one side of the airline, you could request a special bottle of oxygen for a fee, on the low cost side you couldn't.
so, a passenger on the low cost side, shows up with a nice note from her doctor saying she should have oxygen while flying. I called our medical consultation company, spoke with a doctor and made the decission to NOT carry the woman passenger. We made it clear to her that she could get a ticket on the high cost side and pay for oxygen, but the low cost side couldn't accomadate her and she was risking her health by flying without it.. ( we didn't carry animals on the low cost side...but we did carry baby chicks as cargo...and that's another story, especially since baby chick farts can trigger a cargo fire warning, but I digress).
Well, the company backed me up and we didn't carry the passenger. Special medical situations which can be dealt with on the ground, should be dealt with on the ground.
Certainly, if someone who was in reasonable health and then had a problem inflight would be given as much help possible including a medical diversion to nearest best help