Complex sentence: Second was Hamish (born 1895) who emigrated to Canada and served the Canadian Bank of Commerce until he was the bank's Chief Inspector at the Toronto head office; he died of a heart attack in 1949 aged 54.
Split into simpler sentences: Second was Hamish (born 1895) who emigrated to Canada. He served the Canadian Bank of Commerce and was the bank's Chief Inspector at the Toronto head office; he died of a heart attack in 1949 aged 54.