Had a phase of devouring Spark, but haven't read her for ages. I remember The Abbess of Crewe quite well but hadn't connected it with Watergate. As some excuse, i was not quite seven and in hospital myself for part of 1974! Time i looked out Memento Mori, methinx. Oh, to be a speedier reader...
How traumatic your brother's illness and death – that would certainly blur a few years. (When Diana died in 1997, i'd been horribly bereaved less than a year earlier and remember feeling completely detached from the world's reaction to her death.) I hope good memories of his life have helped you since.