Query Regarding Property - Property in name of demise regist

Query Regarding a Property My grand father has written a Will regarding the property as it will be to his 2 sons (excluding 3 daughters) if they look after him. It has been transferred from Grandfather's name to two of his sons after his demise during the FY 2009-10. Later on in 2012 they approached a Builder and they planned to build a flat - 11 no's were in the builder will keep 5 and rest 6 to the sons. On 2012 the property was transferred a at registrar from deceased father name to son's name. They approached rest of the 3 sisters and told them that they will gift them if they provide some amount of cash. They paid and the 2 houses were transferred to the sister's name. Rest 3 houses is in their name in which 1 is joint. Overall the 1 house of the gift was pending. Here the party begins.. They approached third sister and asked for the amount and the sister told after the completion of the flat we will pay. But the thing changed after the construction completed they had asked with interest. Though it was rejected. They smartly told us they will sell the property but even after the 5years completed they could sell the property. Then we started with our ground work to check the reality. We approached City Corporation and we told about the area and ward. We got all the data there but the surprising part to us was 1 flat is in the demised person's name (father) where in I can see as gift in mutation states as daughter (name not mentioned area 0.00.53.0). I just wanted to know how come it is in the name of demised person when he is no more?? Is there any possibility by them to sell?? Is there any possibility to make a claim of property?? Hope for the best. Thank You. Best Regards Vaman