I may have found some of the family together in Montreal on the 1861 census.
Wm Robertson, pattern maker, born Aberdeen, Scotland, religion Church of Scotland, 24, male, single
Margt Robertson, milliner, born Aberdeen, Scotland, religion Church of Scotland, 21, female, single
Nat. Robertson, millwright, born Aberdeen, Scotland, religion Church of Scotland, 19, male, single
Alex Robertson, clerk, born Aberdeen, Scotland, religion Church of Scotland, 17, male, single
John Robertson, clerk, born Aberdeen, Scotland, religion Church of Scotland, 16, male, single
George Clarke, carriage maker, born in Canada, religion Church of England, 23, male, single, not member of family
I can't find Charles or his sister Ann on the 1861 census nor can I find any of them on the 1871 census.
Jacquie