Will Land Property

My grandfather wrote a will before he leaves this world. will is non registered but a notary will write by a lawyer with witness alive. in will he clearly stated all the property to my father alone but he also issued registered gift deeds of land to two of his daughters. Hence the land was not numbered or any sort of specified in gift deeds and in will one of the daughters sold most prime located piece from land without any of our consent and keeping is in unknown. and now she is threatening us that she is going to claim 1/4 from remaining all of property as her right and land she sold was only of hers. and said she do not honour will as its not registered and can easily challange it in court. Was the transaction of the sale of the land she done without our consent was legally correct. Can a perfectly fine will get challenged in court only on the basis of not everyone gets equal part. please educate me on this matter