Daughter-in-law is harassing her Mother-in-law and beats her husband with the help of her 16 yr son

I am having one query regarding one twin property(a 3 storey house) in Delhi which is in the name of the deceased husband(Plot no. 82- 25 Sq yard) and the surviving widow(Plot no. 83- 25 Sq yard) in one JJ Colony. The husband was working and he had constructed the house. The couple has two children- one son and one daughter, both married. The son(45 years) is having no income from any sources and very weak, health-wise and also smokes and completely dependent on Rental income coming from one flat. He has two children- one son aged 16 years and one daughter aged 6 years. His wife is doing Gundagardi(Hooliganism) with the widow mother-in-law who is 70 years old and walks with the help of walking stick as she underwent big spine surgery. The surgery was done with the help of her daughter. Taking the benefit of this whole situation, her daughter-in-law wants to let her weak unemployed husband and her mother-in-law die as soon as possible and possess the whole house for her children. The son also has no mercy for his ailing mother but the mother wants to protect her son from the bullying of her daughter-in-law. The son is getting beatings from wife and his own 16 yr old son. The Power of Attorney for one plot of 25 Sq yard has been taken away forcefully by the father of the daughter-in-law. Query-(i) Can the widow sell the whole house? (ii) Can she stay with her daughter and gift her the whole house under Gift Deed? (iii) Can she inform the Police Station that she is getting the death threat from her daughter-in-law? (iv) How can she get back the property paper taken away by the father of her daughter in law? (v) Can she get the other 25 Sq yard plot registered in her own name as her husband in no more? Kindly guide the course of action available for the widow who is being tortured day and night by her daughter-in-law and not even getting two times meal in that house.