property division

Whether your mother and father has died intestate or executed any will for the property purchased in the name of your mother?

In succession your father had a share with you in the property owned and left behind by your mother.

Further on the death of your father his share shall equally devolve upon you + your stepmother and her daughters. 

Accordingly calculate your share.

It is advisable to consult and engage a local prudent lawyer for better appreciation of facts, professional advise and necessary proceeding.

You have rights over your mother & brothers property. 

The parents, spouse and children are the immediate legal heirs of the deceased person. When a deceased person does not have immediate legal heirs, then the deceased's grandchildren will be the legal heirs.

Your mother owned 10 bighas (your first posting mentions 12 bighas) of land when she died in 2001 and, the property being intestate, would be inherited equally by you, your brother and your father. 

When your brother had died in 2010, he had 2+10/3 (inherited from the late mother) vested with him and, being inteste would be inheirted by the legal heirs. 

Inthis case, there are no Class I legal heirs; there are only Class II legal heirs and according to the provisions of Section 9, father inherits the whole property.

(9. Order of succession among heirs in the Schedule.—Among the heirs specified in the Schedule, those in class I shall take simultaneously and to the exclusion of all other heirs; those in the first entry in class II shall be preferred to those in the second entry; those in the second entry shall be preferred to those in the third entry; and so on in succession)

Thus, when the father had died in 2017, all the property, except the 10/3 bighas you had inherited from your mother, belonged to him and such property would be shared equally among you, your step mother and the step sisters. All of you are Class I legal heirs.

In other words you are entitled to get 10/3 bighas + an equal share in the father's property.