Hi Donald,
It’s great to hear from you! I have been researching John and his family for the last year and a half. The Digital Archives (http://collections.mun.ca) at Memorial University, especially of old newspapers, has been the main supply of information so far. The Newfoundland Grand Banks has also been very useful.
No sure if you are aware, Mary also moved to NL and married William Frew.
John was married twice and had 11 children in total. William was the oldest and actually moved back to Scotland to study and practice medicine. I would guess that was with the help of Campbell.
Most of the children moved away from NL. Of the nine that survived, I think only the oldest daughter, Leah, stayed in NL.
Thanks again for the information!
Cheers,
Ian