The best advice would typically come from a real estate professional experienced in short sale transactions. Assuming loan modficatjion has be looked and not a viable option, the real estate agent can explain the short sale process to the seller, pros and cons, setting their expectation accordingly.
My best advice would be to ensure the home owners actually qualify for a short sale option. Check the IRS website as well as lender websites and various ACTs put in place to guide those interested in short sale options. You will find majority of home owners do not qualify for this option. Depending on the individual's situation there are many options available. Learn all you can before putting yourself and families in a situation that may result in failure. Best of luck to you!
Short sales are probably more widely used than most people think. The real determination is made by the lender. I have even seen sellers of investment properties accomplish a short sale. It's all about preparing the lender required documentation and being prepared to follow through with the lender's procedures. Seek out an agent who has actually been through the process a few times, and you will find the journey will generally be a smoother one.