Ref. No. 1018/41-171
In the name of Allah the most Gracious the most merciful
The answer to your question is as follows:
The whole asset of the wife will be divided into 42 shares. 7 shares would be given to her mother and 5 shares to her sister, and each brother will get 10 shares.
And Allah knows best
Darul Uloom Waqf Deoband