X and Y sold a piece of their ancestral land to A with a RS 20 bond paper unregistered in 1987; in 2004 A registered by a gift deed to his wife B; B constructed home and property tax, power bill, etc., being paid from last 16 years on her name. In 2013 B sold the property registered to C;
X expired long back; now X's son Z put a petition in the court against A, B, C for a share in this property. Is the case valid and how should C proceed further?