1) there are 4 legal heirs as your father died intestate ie your mother , you , your brother and sister
2) if original documents are lost obtain certifed copy of said documents from sub registrar office
3)your mother and sister can execute gift deed to transfer their 1/4th share in property to you . gift deed has to be duly stamped and regd
4) in many states gift deed in favour of family members attract no stamp duty or nominal stamp duty of Rs 500 or so
5) you would need your brother consent to sell the house in faridabad . offer him his 1/4th share from sale proceeds