First of all, clearly this was a very sad occurence and my thoughts go out to their friends and relatives and my comments are in no way a criticism of anyone involved with the flight.
Private aircraft owners or people who regularly take their partner and family flying should strongly consider having their non-pilot partner undertake a "pinch seater" course, to enable them to have a chance at landing the aircraft following the incapacitation of the pilot. Say around 10 hours of training to understand the basics of the controls and how to talk to someone on the radio. It would not always help eg at night in cloud, but it will certainly save some for a reasonable cost outlay.
Secondly, I am always amazed at the commercial pilots that seem to be able to maintain their medical to Class 1 standards given their obvious obesity, smoking, lack of exercise and out of scale BMI. Those questions that the DAME asks at the start of the medical are supposed to mean something surely?
I realise that the other side of the coin is that an otherwise fit and healthy person can be incapacitated for any number of unforseen or unforseeable reasons but surely tightening up on those people who are obviously a heart attack waiting to happen would be a move in the right direction.