At the end of the day - the airlines refused to fly her home because in the opinion of the Captain, her presence on board was a safety risk for the woman herself and other passengers.
In the case of an emergency, there was no way this woman and her husband could have got themselves off the plane, and she had difficulty even getting through the aeroplane door.
Getting her off in an emergency would have been at great risk to the cabin crew who would have had to stay and at least try to help her, and she would have blocked the aisles and/ doors for the other passengers. Anyone who requires the assistance of more than one or possibly two people is a danger to themselves and others on a flight.
The husband deserves NO compensation - they should never have travelled with her in such a fragile state of health, and they should have sought appropriate medical aid in Europe before attempting the return journey. People need to take some responsibility for their own actions and decisions