We are a family of ten children: five sons and five daughters. Before passing away, my father registered all his lands in the names of his sons, but not the daughters. He did this under the pretext that he wanted to secure their future and make sure that they are provided for. As for the daughters, they, as he said, are married and needed nothing. What is the ruling of Sharia on this? If what he did is impermissible, what are the sons required to do?