If your deceased husband left some wealth leaving you (wife), mother, one sister and one brother as heirs and there are no other heirs of him, then all the property of the deceased shall be divided into 36 shares as per the Shariah. Out of the total, you shall get one fourth (9 shares), one sixth (6 shares) shall go to his mother, 14 shares to the brother while 7 shares shall go to the sister. You can keep as much share you have in the inheritance, and then should give the rest one to the Shariah heirs. The detail of the division is as follows:
Allah knows Best!
Darul Uloom Deoband