What is married daughter's share in her late father's property, advise

Sir i am 68 years old 75% disabled ex-serviceman pensioner and cannot move without crutches living in a rented house on the mercy of my son. He is 35 years and has refused to marry until has his own house. My wife has one younger and two free hold houses in delhi (300 Sq meter and 200 Sq meter) He is residing in 300 Sq meter with two daughters, wife and mother since father expired in 2004. My wife is very docile and too scared to talk to them asking for a place to reside whereas at least 06 floors can be constructed in both houses. It is pertinent to mention that the second house was given on rent to a businessman in 1960's and could not get it vacated for decades and then requested my consent since there is some law that a disabled ex-soldier is entitled to get the premises for self use but after vacating orders in around 1999 they have given it on rent again. Is there any solution Ethical , Moral , Social or legal. Regards