The same thing happens to a body when the soul leaves. It just lies there. I went on to make two clarifications to my young caller. First, souls aren't actually in bodies in exactly the same way a hand is in a glove. Our hands are physical, but our souls are not.
Souls are invisible, but they are still real.
Second, if we wore gloves all the time and never took them off, some people might say we didn't really have any hands at all because they never saw them. They'd say that gloves were the only things that were real, that hands didn't actually exist. This would be a mistake because when we look closely at gloves, it becomes very clear that they would not be able to do the things they do all by themselves. Hands do things that gloves alone can't do. In the same way, souls do things that mere physical bodies can't do.