What about Mrs. Pollifax’s adventures written by Dorothy Gilman?
Flashman (suggested above by glaeken) never appealed to me - he’s too much of a psychopath. As an alternative, you might try the Sharpe novels by Bernard Cornwell, or look for the British TV series.
I’m currently reading The Manchurian Candidate by Richard Condon. It isn’t great writing, but it has the Cold War, spies, a thinly-disguised Joseph McCarthy, and a brainwashed assassin. What more do you need? (The Frank Sinatra movie was pretty good too.)
The Rumpole novels by John Mortimer. My parents like them, and they’re about your father’s age.