Property selling

My uncle with his own business income had brought a land of 2 acres in his own name in Karnataka state,about 20 years back. He has one son and 5 daughters. All his children are married and they're living separately. Now my uncle want to sell his land of 2 acres, which is objected by his only one son orally, who is not interested in selling the land. My uncle challenges that he will sell the land without considering any of his heir's permission/approval/signature. Is it possible to sell the land by not taking into account of his children ? Is there any law or rule to sell the land on his own ?