بسم الله الرحمن الرحيم
In the above mentioned case, the blood which the woman is experiencing it is of menstruation. If this blood exceeds ten days then the habit of the woman shall be taken into consideration i.e. as much days she used to experience before the pregnancy that much days shall be counted as menstruation. The extra days shall be deemed to be istihazah blood (bleeding). Hence when the days of menstruation cycle are over, then the woman should have ghusl and keep on offering salah during istihazah days by making wudhu, but if the bleeding continues so extensively that it covers the whole time of salah then she shall be deemed mazur (excused person) according to Shariah and in this case the ruling is that she will make wudhu at the beginning of salah time and will offer as much salah as she wishes within the time and then will make fresh wudhu for next time of Salah and the blood which discharges in-between would not have any effect on the wudhu.
والمرئي (أي الدم المرئي مع السقط الذى لم يظهر من خلقه شيئ) حيض إن دام ثلاثا وتقدمه طهر تام وإلا استحاضة (الدر المختار مع الرد 1/501) ودم استحاضة حكمه كرعاف دائم وقتا كاملا لا يمنع صوماً ولا صلاة (1/495)
Allah knows Best!
Darul Uloom Deoband