Thanks for all the response. I think it depends one how much under water she gets. If she goes say $300,000 underwater, it might be worth it to go out and buy a new lower-priced house then walk away from the old one. Even if one could afford to make the payments, why would anyone want to keep on paying on such an overpriced house. It only makes financial sense to me to let the lender deal with it.
It’ll tell her to talk to a lawyer if the markets really tanks.