بسم الله الرحمن الرحيم
(1) In the above mentioned case, all the property of your father became his inheritance after his death. The property of a man after his death is divided among all his legal heirs according the Shariah, after paying due rights preceding inheritance. Only one heir cannot take all the property. In the above mentioned case, all the property and wealth of your deceased father shall be divided among your mother, brother and sister. It shall not be given to your mother only. In the above mentioned case, if your grandmother and grandfather were not alive at the time of your father’s death then all the wealth shall be divided into 40 shares. Out of the total your mother shall get 5 shares, 14-14 shares shall go to each brother while your sister shall get 7 shares. And if you people (you, your younger brother and sister) after taking your shares of the property hand over it to your mother and she takes care of everyone’s shares completely and spends in the need of everyone as per his or her requirement then there is no harm in it. However you should avoid from all those things that may cause dispute and difference among you right now or in future.
And if your father made a will during his lifetime to transfer all the property to his wife, and you along with your brother and sister agree to transfer all the property to your mother as per the will of your deceased father, then write the whole detail and submit the question again.
(2) If your father had received that land from his father, mother or relative and your father was its owner then after his death it shall be divided among you. It is not lawful for your father’s brother (your uncle etc) to usurp that land illegally. You people may claim for that land. You may also adopt any legal method to regain the land.
Allah knows Best!
Darul Uloom Deoband