To take care of the home and the kids while the dad provides the main income (at least I think that's how it should be), although honestly, even if the dad takes care of the kids and the mom provides the income, at least he's still helping, doing things such as taking care of the lawn, fixing cars, doing projects around the house etc. and not crying over misgenderised things.
If she doesn't want to do that job, then she can get a job she wants. It's America, can she do whatever she wants if she doesn't want that kind of job.