Is the widow obliged to give the brothers of her deceased husband their share of the building costs that the husband spent on a house owned by the wife, or is that permissible for her and her daughters, given that the husband built willingly on her private property?

If the wife gifted the space above the commercial property to her husband for construction, then the house built by the husband upon it is considered part of the inheritance and is to be divided among all heirs. However, if the wife only permitted him to build without gifting the space, the building is considered the husband's property, and the wife is deemed to have loaned him the space. This loan (عارية) ends upon the husband's death, unless the period between construction and death was short, in which case the loan continues for the customary duration. At the end of the loan period, the wife must pay the heirs the value of the building, whether demolished or standing, and the building then becomes her property. In case of dispute, the matter must be settled by the Sharia court.