Does the father's wife have the right to inherit our father's apartments, which our mother contributed to building, especially since our father allocated a rental contract for an apartment to her and she owns her own pension?

One should not inquire about inheritance while the owner of the wealth is still alive, especially if the father is the owner of the wealth. The legitimate principles of inheritance stipulate that what a deceased person leaves behind is a right for their heirs. The wife has her share, as stated in the Almighty's saying: "And for them is one fourth of what you leave if you have no child. But if you have a child, then for them is an eighth of what you leave, after any bequest you [may have] made or debt." The mother's contribution to construction is not considered part of her estate unless it is proven by evidence that she contributed with the intention of recourse against the father. The maintenance of the wife, including housing, is obligatory upon her husband, even if she is wealthy.