Hi Mark

On the Isle of Man , it was more common to name first son after Father's father, second son after Mother's father , third son after Father.
I see he died August 9, 1928, Waterloo , Black Hawk County , Iowa. And note that Cassie was 28 years younger , and his children were not named in the Manx/Scottish way. Was it his second marriage ?
Have you tried U.S. Immigration Records or Citizenship records ?

Cheers
David