related to not vacted the property

immeidate possession she wont get.  Either she has to take police help or file a suit for possession in the court by giving a notice u/s 106 of TP act before filing the suit.
 

You are talking about provisions of Delhi Rent Control Act . There is a summary procedure in such cases proved in sec 25-B. Heavy burden is cast upon tenant to show the requirement of the widow is not genuine

Sir, I own a house purchased and registered on my name. I bought this property while I was serving in defence service to keep my parents and other family members. Due to my frequent postings in defence as every body is aware, I could not stayed in my above purchased house and hence, I allowed my parents and other family members to stay in it. Now, since my parents are no more on the earth and other family members i.e. brothers and sisters settled at their places after marrying or so, one of the brother who got the court marriage and left his spouse, now staying in the same house and not ready to vacate. I had put my hard earned money to buy the said house. He is is not willing to vacate. I sent him letters but no awail. Please suggest me the rules and regulations under which I can get possession of the same from duly got vacated by him. Can I rent the same property to him charging rent? What papers shall be executed to make him regular paying rent, if so. I also intend to sale the property and buy another one for my wards. Kindly suggest me your suitable advice/rule through which I could go ahead and take action. Regards.

From the facts, it appears that it is only a license given to your brother to stay in the house. 

If you want to take back possession, you shall have to give a notice  to him to vacate it and if he does not do so you shall have to file a suit for possession and damages. After getting back the possession you are free to sell it.  If you want to rent out the property to your brother and if he is willing to enter into an agreement, go ahead and agree for a rent more than the rent on which rent control act of the state does not apply.