Your mother should sue her brother to recover sale proceeds of land sold by him 

contact a local lawyer 

It is mother inherited (self acquired) property.  None children have any say and she can give her property to any child.

Even If she has been induced sell property, trasfer to daughter and amount kept by brother, you have no say. Your mother only can file case to recover. 

IF you have any children or any grand child is born than property has acquire ancestral status and you have share in it.  You can file partition suit to claim your and you son share from total land and sale amount.

If your mother alone inherited the land, then it becomes her private property and she may do as she pleases with the land in her lifetime. However if you all jointly inherited the land and if you all have a share in it then she cannot sell it off alone.

Now in case you mean to say that though your mother owned the land but your brother has cheated your mother and fraudulently got the land sold and took the money for himself then she can file a case against him to recover the money and she can also proceed criminally if she wants. There is another option of getting the sale set aside on the ground of fraud but that will be too complicated in your case since if she wins, the court will ask your mother to return the sale proceeds which your brother may not be willing to do and even the framing of such a suit will be too complex. Similarly In the case of your sister she can file a case for setting aside the deed of sale on the ground of fraud or simply recover the money from your brother by a suit. All the money will still be her since she owned the property and the children only get a share after her lifetime if she does not make a will to the contrary.

However if you all inherited the land and your brother got it sold then the sale is outright illegal and void since she could have only sold her own share and you can file a suit for cancellation of the sale deeds.

Here children are not entitled to ask their share in the inherited property by parents and especially mother. In  your case your mother becomes the sole owner once the property is inherited from her parents. So you nor your other siblings can claim any share in the property. you can have word with mother for remaining property distribution and can taking remaining land in rest of the siblings.

1.  "IF" you have documentary evidences & witnesses to the events & circumstances stated by you, THEN you (as a legal heir) have a strong case to stake claim of your share ratio, in Mother's original & subsequent share of property, via a Partition Suit, to be filed in the local Civil Court.

2. Similarly you can also obtain a "restraining order" from the civil court, directing Mother & all other legal heirs, from disposing or alienating her property.

Please file partition suit before Civil Court for the proper division and distribution of moveable and immovable properties held by you ,brother,sister and all legal heirs related to blood relative and same class. 

1. First take note that the property belonging to your mother is deemed to be her self acquired or exclusive property and hence she can gift this or give its sale price to anyone she so chooses.

2. Now in reality if your mother has been defrauded in selling her property and she doesn't know what actually is going on then only she alone can file such suit to declare the sale as null and void. 

3. So first talk to your mother and then take a decision on this. 

You all legal heirs need to get a relinquishment deed executed in favour of your mother. 

- As per Muslim Law, there is no distinction between the self acquired or ancestral property. 

- Further, legal heirs are divided into two categories: sharers and residuary , and Sharers get their share first and residuary get what is left.

- Further, if a Muslim woman inherits property from any relation , then she becomes the absolute owner of her share and can dispose it , but she cannot give away more than one-third share of her property, and if her husband is the only heir, she can give two-thirds of the property by will.
- Further, if your father has already died , then your mother can sell or transfer 1/3 rd of the land only , and remaining would be distributed between her children. 

- Hence, out of all the land except one third  i.e. 25% , she cannot sell or transfer to her a single son or daughter  , you and your brothers right is equal and sisters right is half of one brother. 

- If your said brother refuse to share the sell proceed and distribute the property , then file a partition suit before the court. 

File a Partition suit 

Under Muslim law, the concept of ancestral and self-acquired property is not recognised

Please contact local property lawyer in this regard. 

The property inherited by your mother from her parents becomes her own and absolute property. 

Nobody can claim any share in the property as a right. 

Your siblings were intelligent enough to convince your mother and grab whatever that was possible by them.

You may also apply similar strategies to get a share in the property somehow. 

Legally you may not be able to get any share out of the property even if you plan to approach court of law. 

Dear Sir,

You are suggested to ask the share from the younger brother/mother from the sale proceeds of earlier occasions and also file the case of injunction against him and mother for stopping them for further sale. 

You cannot file suit to claim sold property by your mother but if you can convince your mother to file suit for cancellation of transfer done on name of sister then only you can ask your mother for equal distribution among all children.

Otherwise you can only claim share from property which is left after sale or transfer of property.