Will-registered by a person and spouse added someone on the other will

A house property was in the name of a wife and she written a Will and registered it. She died. Husband was living in the property. In that will the beneficiaries can only get their part after her husband's death. But the husband built a first floor on the property and rented to someone. And then the Husband wrote a settlement or Will which says that the newly built first floor will be given to a relative(one of the beneficiaries in the original will) who took care of him for few years. Now the husband also died. The executor doesn't know about it. Whether this new will or settlement is valid?