Draco would be able to claim the heirship, when he was seven, but first he was registered as heir and Narcissa was accepted as the regent of the house Black by the family magics and was now the head of the house Black. As head, she was able to decide, what would happen to certain family members and would make major important decisions for the family. First things first, she called upon the family magics, in order to test her sister Bellatrix and her cousin Sirius, if they were even worthy to hold the name Black and the Black family magics due to their actions. When she felt the rips, she was saddened that both were unworthy and were now disowned. From that day their names were Bellatrix Lestrange formally Black and not neé Black, because she was no longer accepted by the Black family to carry the name and magics, but her sister would not suffer the rips of magic, because the Lestrange family magics would replace the loss of the Black family magics. But she would be a lot of weaker than before. Only, if she was divorced, then she would be Bellatrix NoName (formally Black) and with the divorce she would lose the Lestrange family magics and that would be painful, but she didn’t believe that Rodolphus would divorce his wife. But her cousin, Sirius, would suffer the pain of a magical disownment, and from that day his name would be Sirius Orion NoName. She had expected that at least one of them would be worthy to remain a member of the Black family, but with a pang of disappointment she realised that none of them were worthy to hold the family magics and name due to their gruesome actions.