I think Kristina had a some valid points about the luncheonette, but not towards Jasmine. She and Adam should have discussed the decision thoroughly. He decided to delve back into a failing business while:
1. eldest child is in a very expensive school
2. middle child has special needs
3. another child floating around somewhere
4. they are in debt because of failed mayoral campaign
I am sure that Kristina is making some money as principal, but probably not enough considering how they are living. She needs to be part of the decision to risk her family's financial solvency for the business. But that is a discussion she should be having with Adam, not Jasmine.