Is it permissible for daughters to demand a share of the building or an equivalent rent for the apartments after the father's death, if the father had given each of his sons an apartment to live in and married off all the children at his expense, knowing that all the daughters are married and the sons are poor and have no money? And is what the father did Islamically correct?

The fundamental principle is the obligation to be just among children in giving and gifting. It is forbidden for a parent to favor one of them unless with the permission and consent of the rest, or due to severe need, such as poverty or debt; this is an exception to the obligation of justice. If a father gifts his children during his lifetime by way of ownership, then that becomes their property and does not enter into the inheritance. However, if it was a loan, then it returns to the estate and is distributed by the heirs.