levy and execution on a home

My clients own their home and a judgment creditor (without a mortgage) is trying to levy on it. They obtained a writ of execution. My clients have a homeowners' exemption and large first and second mortgages and their home is underwater. The attorney for the judgment creditor says he can seize the home and dispossess my clients even though they may later prove that there is no value in the home so they should get to remain living there. I'm trying to help them stay in the home pending a determination by the court on the value of my clients' interest (which we believe will be zero). The question in a nutshell is whether the Writ of Execution gives the creditor the right to turn it over to a sheriff and seize the home pending the execution sale (and pending appraisal and determination of whether my clients have any equity).