My mom has pictures of Robert when he was young and my mom calls them pictures of "little Bobby Pipes", but I will have to check if he was actually called Bobby, we call him a lot of things, butmostly Bob and Robert ;)
I was under the impression his father had died much earlier, but I could be mistaken, I only met Robert in the early 70's.
As far as I know, he was an only child. Unclear whether you were indicating your father-in-law as child of Harry, Jr. or child of Alfred.
I will try to call my mom today and see if I can attain further info. I am making a list of questions for her so hopefully I won't forget anything.
I'll post here what I find, in case anyone else needs the info.