Grandson's rights on grandfather's self acquired property

Hi All, The reason behind this post is my grandfather and grandmother are disappointed by uncle behavior and day by day my grandfather spoiling his health(heart patient) due to my uncle and aunty wired behavior. They were asking to transfer the complete property on their name. There is no issue to transfer the property if they take care of them but they are like least bothered about them. Even we had tried in many ways to settle this and offered lot and my grandfather need to pay nearly 40L to other for the loan. If we transfer full property to my uncle for sure they will look after my grandparents. My questions are: 1) My great-grandfather has a land of 300 sq yard and transferred to his two sons one is my grandfather got registered that land as normal registration and second is his brother got registered as gift registration on their names when he was alive and my grandfather constructed a house on that land. Now my uncle is saying that is an ancestral property and it belongs to me and you don't have any right to sell it. 2) My grandfather purchased lands on his name and on my grandmother name. Do my grandfather can sell that lands or he can make a will?? Is that will paper is valid? 3) There is a land which is registered on great-grandmother and as per my knowledge my uncle can ask equal share on this property and even we can agree with this. If we checked with a local lawyer, he was saying that my uncle will have right on the all self-acquired properties of grandparents. As per my knowledge once after registering the land from my great-grandfather to grandfather when he was lived and my uncle doesn't have any right to ask share on that property and on the self-acquired property until their last minute. Please suggest me how to proceed... Thanks in advance..