Rahul Mehta Gandhinagar LsCandidate

I have following question on Hindu succession act. I request lawyer or any informed person to reply , with citation of acts is possible.
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PLEASE COMMENT ONLY F YOU HAVE READ LAWS
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1. A Hindu man X had Hindu wife Y and four sons A to D, all Hindus
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2. X died in year 2006. He had one huge plot earned from his own income , not inherited and no other property. It was transferred in the name of his wife Y
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3. Wife Y died in year 2012. Y in her will wrote that plot will become property of A and B, and left nothing for C and D.
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4. Is her will valid?
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Can a woman away all her INHERITED property to two sons and debar two other sons?
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And was transferring plot to wife's name legal? Because shouldnt the plot be divided into 5 parts --- Y and A to D?
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