Sir Alec Bristow is the adoptive father of Charlie, John and Lula, and the husband of Yvette Bristow (nee Landry). Alec is said to have adored his wife and indulged her quite a bit. He was already deceased by the time of the events in The Cuckoo’s Calling.
In the book we find out that Alec and Tony Landry (Yvette’s brother) didn’t get along after Charlie died; Tony had said something to Alec which resulted in Alec punching Tony. We don’t find out what it was that Tony said to Alec until the end of the book.