You need to find a Realtor with short sale experience. From the lender's point of view, it is better for them (that means costs them less money), for a short sale than foreclosure.
Sometimes if a sharp Realtor contacts the bank they can negotiate the best outcome for your family. This means if they, as a professional, contact the bank, the bank knows that you have made decision not to just walk away , but to try to do the right thing.
There is such a thing as honor. You have a debt. A mortgage is a promise to pay. Let them know that you are honorable people and are not abdicating your responsibility. You may be surprised. They may honor your commitment and help you.
If you need a referral let me know.