Is it permissible for the wife to demand the money she gave to her deceased husband before consummation, to help him furnish the house, from his heirs?

This woman may revoke her gift to her husband if the purpose of the gift was not achieved. For instance, if she gifted him something to help furnish the marital home, but the marriage did not take place or he divorced her, then she may revoke what she gifted him, due to the non-fulfillment of the gift's purpose.