Q: A person who was studying in the city of Tabuk came to our town of Rabwa in 1393 A.H. While he was in my house, he saw my mother performing Salah and standing after making Ruku` (bowing). When she finished Salah, he said to her: "My mother, a woman's Salah is different from that of a man." She asked, "How, my son?" In reply, he said, "If a woman says Takbirat-ul-ihram (saying: "Allahu Akbar [Allah is the Greatest]" upon starting Prayer) and performs Ruku` and Sujud, she should continue her Salah in a sitting position and she is not permitted to stand up for every Rak`ah (unit of Prayer), even if she is capable of standing." My mother continued performing Salah in this manner from that year on. At the time, I was young and could not discern the way she performed Salah albeit she is totally able to stand up in Salah. Now, I turn to Allah (Exalted be He), then to you to give us your Fatwa in this regard. If her Salah in the way mentioned was invalid, is she obliged to make up for the Salahs offered during these years?