So you're suggesting that she make a fake refugee claim? Horrible idea.
She's coming from the UK. So clearly there's no grounds for claiming refugee status since the UK is perfectly safe. Canada is also now expediting refusals for refugee claims that have no grounds. She would fall into this category coming from Brazil and living in the UK. So she could be removed from Canada quite quickly. Once she is removed from Canada for a fake refugee claim, any future entries into Canada become much more complicated (including spousal sponsorship).
Again, absolutely horrible idea.