Please come to Gringotts, in order to register your son as heir. We also cannot produce the name of the former heir, because the said boy changed his name legally and magically. It seems like that Lady Magic herself accepted the boy’s name change, because even in our records, he had disappeared like he had never existed. I am telling you this now, because if the boy rekindles the broken bond with his former godfather, Sirius Black, then he will be able to challenge your son to return the heirship and your son will be forced to give the heirship back to the former Potter child since he has been the original heir, announced by Arcturus Black III.