The soul is simply an observer
The body goes its own way and does its own thing according to the laws of physics. It is an automaton. God does not watch humans from outside, he watches from inside using parallel-processing. Souls do not exist as such, they are a part of God's consciousness - the consciousness of the universe. God is the universe and souls allow the universe to observe itself from within.
Imagine someone watching millions of TV sets at once (rather like security camerasmonitors in a large building). If one set dies, the observer remains the same. As long as one TV remains, there is something to watch.
When a body dies, it's no different from, say, a TV breaking. God no longer has a way of observing anything in the physical world through that particular mechanism.