Proces available to senior Citizen for vacating his house

My Father who is 75 year who used to be newpaper seller in Delhi, purchased a land around 15 year back in east delhi, out of his hardearned money. He again worked hard and build two room set on that land around 7 year back. In order to meet his expense and having a sense of self depended, he rented out property on March 2016 to tenant with lease agreement Rs 50 (no registration and only simple attestation/notary has been done). Suddenly on one date, there was flight between tenant (husband and wife) and husband left the house along with all of his belonging when his wife was out for one night. When his wife came, she claimed that My father and her husband theft all her belonging and put a lock on main door of our house. Police is also favouring her on the ground that 1) She is a lady 2) Local NGO is supporting her. Now the latest situation/question is summarised as follows a) My father is 75 year old and already got 2 heart attack and currently having heart beat around 55 per minute b) he is continously harresed by women since women is not staying in our house but kept it locked. c) My father also keep running to police station but no help d) Since the main gain is locked he even can not go to the second room (out of two room only one room was lend and second room is with us). e) Tenant is not staying in house for past 3 month and vacated house but his wife is claiming that she will not leave house f) In order to apply application under Delhi Rent Control Act,, there has to be tenant....But tenant already left.....Should be still go for Rent control act (claiming the house for personal use based on age factor and advise of doctor not to climb stair) or Civil court. Please advise to the earliest possilble about how to handle wife of tenant, Women NGO and local police