I doubt it is the family that have either instigated or `need this'. It is the country. It is respect.
If he had been the husband of any head of state, world wide, his death would have been suitably recognised, as this is being suitably recognised right now, in countries all around the globe.
If he had been the equally long-serving, well known and almost universally recognised (with respect) partner of the head of state of any country in the world, his passing would now be being marked in much the same way.
Though not identical - and for different reasons - the closest illustration I can think of, for that, is the death of United States President, John Kennedy. Within minutes of the event the whole world knew, and responded with due respect.
I was at a film showing, in the dining hall of my college `res' when that news came in. Everything stopped.
And I was miles away on another continent, in the middle of central Africa.