Thanks, Kevin - it wasn't old news, since I haven't gone systematically through all of the versions of 68 on Richie's site.

"This is the only other American version to mention the father-in-law inquiring about his missing son (as far as I know)."

There is a clear similarity there: unusual for 'father-in-law' to be mentioned at all, and the phrase 'my heart will break with sorrow' is common to both. Not sure what it might mean, though!