I have no idea what happened to Isadore's children. They were not living with Harvey and my gr.gr.aunt in Toronto. I have just received some information on Harvey's first wife and son. Evidently Harvey and his first wife divorced. Adelaide Blandmond later married Harvey's brother William and they moved to the Philipines.
If you contact me off list at email@example.com I will give you the email address of another researcher who seems to have a great deal of information on this line.