All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
What your brothers did, which is registering the remaining land on their names and your mother agreeing with them and helping them, all this is not permissible. This is because after confirming the death of your father, the land has become a property of all the heirs and no one of them has the right to exclusively appropriate it for himself and exclude the remaining heirs.
Also, your father favoring his two youngest sons by gifting them part of the land (excluding the other sons) in his lifetime without a sound reason is not permissible. However, would this be valid or not valid after his death? There is a difference of opinion among the scholars regarding this, but most of them are of the view that it becomes effective after his death.
What is said about the gift of the father can also be said about the gift of the mother. After dividing the land between the heirs and knowing the share of each heir, it is not permissible for the mother to favor some of her children in gifting them (her share) over some other children as long as there is no sound reason, like need or poverty and the like.
This is in regard to the ruling of Sharee’ah. As regards the ruling of the Indian law, we are not aware of it. In any case, the Muslims should take their cases in all matters to an Islamic court and it is forbidden for them to take their cases to non-Islamic courts without a necessity.
Allaah Knows best.