Many families, while making funeral arrangements for a loved one, will ask for a “watcher” without really knowing the reason behind having one. Many years ago, a watcher was a person assigned to “watch” a body just in case the person was not actually dead as the tests for death were not as certain as they are today. There was also the risk of the body being stolen for medical study by anatomists.
Neither of these reasons apply today yet a watcher may still be requested by an uninformed family that is not observant. In the Jewish religion, the reason for a “watcher” or “shomer” is rooted in the belief that upon the death of a Jewish person, the soul will separate from the body that housed it. As it cannot ascend to heaven until the body is buried, the interval that it is hovering is a turbulent time and the soul needs to be comforted. A “shomer” performing “shmeera” keeps vigil, reciting psalms and prayers that help elevate the soul and prepare it for ascension to heaven where it will be judged by the G-d who created it.
It is for this reason that people who are very observant insist on burial as soon as possible as the focus until burial of the body is on the soul, not the mourners. Once the body is buried and the soul has ascended, the focus shifts to the mourners.