OP,
you were given excellent advice on this in your first post:
Generally speaking, claims that belonged or would have belonged to the deceased belong to his Estate after his death. So the Executor, as the representative of the Estate, is the appropriate person to file suit on behalf of the Estate.
If the executor determines that a lawsuit is not appropriate, either because it is without merit, too expensive, not in the interests of the estate, etc., that is the executor's decision. The executor does not have to initiate litigation.