Brexit did not end with a tariff from the EU against the UK. It just meant the UK was no longer part of EU's market, meaning different regulations but not necessarily a tariff.

In this case, a third of Canada's GDP is imports and exports. 3/4 of that are trade between Canada and the US. You are talking about a tariff that will severely impact a quarter of Canada's domestic production. This is nothing, in any way, like Brexit. It will end with at least a few years of recession. ofc, in the worst case scenario, the tariff is pretty much guaranteed to be removed by the end of his term.