Father in law executed the will, mother in law going against it

Hi My father in law passed away during 2016. He is having a small own house, on our insistence he created a WILL in 2014 that his wife cannot sell the property but can enjoy and eventually this will pass it on to his two daughters. Now, he is not there, my mother in law says to buy either of her two daughters the property by paying the other cash to the extent of market value. If this does not work, all the three of them who are beneficiaries are fine to sell. Is this two things are possible? please let me know