Does the wife stop praying throughout the period of dry and brown blood (approximately 3 weeks), or does she pray after the first two weeks? And how does she perform the rituals of Umrah while the bleeding continues?

The maximum duration of menstruation is fifteen days. If the blood exceeds this period, the woman is considered to be in a state of istihadah (definition) (non-menstrual vaginal bleeding). A woman in istihadah must refer to her previous habitual period if she knows it; she then performs ghusl (definition) (ritual purification bath) and prays after the completion of her customary days. If she does not have a known custom, and if she can distinguish menstrual blood by its characteristics, then she considers what has the characteristics of menstrual blood as menstruation (provided its duration is less than fifteen days), and anything else as istihadah. If she has neither a custom nor a valid distinction, then she considers six or seven days as menstruation based on investigation, and anything beyond that as istihadah. During the days of istihadah, she performs wudu (ablution) for each prayer after its time has entered, after taking precautions (to prevent leakage), and she prays both obligatory and supererogatory prayers. It is permissible for her to perform tawaf (definition) (circumambulation) around the Kaaba during the period of istihadah, and it is permissible for her to enter into ihram (definition) for Umrah (definition) while she is menstruating. However, she should not perform tawaf around the Kaaba until she becomes pure and performs ghusl from menstruation. After performing ghusl, it is permissible for her to perform tawaf even if the blood of istihadah is still flowing.