A sues B, wins a judgment, and can't collect because B has no money. A dies. Is B off the hook?
B dies first. Does A have a claim against B's estate?
In both cases, the estate takes over. If A dies, then B owes the money to A's estate. If B dies, then B's estate owes the money to A.
If B's estate is empty, then the debt is retired, because a debt cannot be inherited.