Upvote:5
The Canadian government websites are not very clear on this point. For example this national website is written entirely in terms of one traveller and makes no mention of a family unit: https://www.cbsa-asfc.gc.ca/travel-voyage/ttd-vdd-eng.html
But this one for Ontario (which I would expect follows the same rules as the rest of Canada) says it's $10,000 per family: https://settlement.org/ontario/immigration-citizenship/landing-and-leaving/landing-in-canada/how-do-i-bring-money-into-canada-proof-of-funds/
Probably the best is just to declare if your family is carrying more than $10,000. You shouldn't get in trouble for declaring when it was not legally required to do so. And you are allowed to carry more than $10,000 so long as you declare it.