To what extent is the written agreement legitimate between a husband and his new wife - a divorcee who cannot conceive - that he will give her a specific gift upon marriage, and allocate a portion of the income from his properties for her, with the ownership remaining with his children should he predecease her, and that she will not inherit from his estate, and that she will remain living in his house should he predecease her for the remainder of her life?

The agreement to waive inheritance before it is due is Islamically invalid. The wife has her share of her husband's inheritance. As for a bequest to the wife after the husband's death, it is not enforceable unless the rest of the heirs agree, because the Prophet, peace and blessings be upon him, said: "Indeed, Allah has given every rightful person his due, and there is no bequest for an heir." This is by scholarly consensus. And with the invalidity of the agreement, the wife is entitled to her customary dower (mahr al-mithl).