Misuse Of Child's Right In A Sold Property.

my younger brother and his wife passed away and left a little daughter(13year old).little girl is living with my younger sister.as she is most comfortable there. (the part of little girl has not been paid yet by buyer due to some genuine legal reason.) my younger sister wants to misuse the little girls right and money over the sold property of his father's share. I have already personally given MANY LAKHS(more than half amount of property share of girl)to my sis.is there any LEGAL WAY so that little girl's right can't be misused.