Sale Deed With Blood Relation Witness Is Valid

Fact come to knowledge that, A late Muslim father has 15 childrens and second one son made a sale deed of land of his Father by misleading and cheating him as lease agreement and keeping 1st witness of his brother and 2nd one is unknown false people and taken hose loan and construct the building. Kindly provide legal advice to make shareholder of all children can we file a case against 2nd son. Against such fraud and chitting with families. Awaiting the earliest reply from any legal advisors on the above. Thanks n Regards Aatiya K