Special Clause/mention In Gift Deed

My maternal grandfather (He had 6 daughters and no sons), The ancestral property by divided between him and his brother. He further gifted a part of this property (2/3rd of the property to my mother as she was the one who took care of him and he stayed with us most part of his life and also my mother helped during the marriages of other sisters (my maternal aunts). The gift deed mentions that my grandfather has gifted the property to my mother for the above reasons. However, he also mentioned in the deed that my mother will not have any right or claim over the remaining property. 1) Can my mother claim a right in the remaining property. 2) Will taking this into court also litigate the existing gift deed and my mother's right over the gifted property can be challenged by my aunts.