SXB, you said: "...the Captain did make an informed decision and he decided to ignore the recommendation of his CC..."
Were you there? How do you know that the Captain's decision was informed or whether he just chose the easier option? It seems to me as if he went with the easier option because he was well away from the smell.
The most qualified people to make the decision are the ones who have to deal with the passengers in question and based on the description of the situation, the Captain didn't even see the passenger.
I'm appalled by the fact that the Captain did not back up his crew!
And by the way, cabin crew are first aiders, not medical staff. There is a big difference between the two.
In my airline passengers with pre-existing medical problems who cannot look after themselves are required to travel with a carer or professional medical staff. Given the description of the lady's condition, her son obviously was not meeting his obligations and as such should have been denied boarding.