Renewal of landlord tenant agreement allowing tenant to continue.

We have commercial property (a shop) in Chandni Chowk, Delhi which was bought and registered in my mother's name in the year 2007. My mother passed away in year 2010. My father rent the property out in year 2011 and signed a registered rent agreement for a period of 5 years which expired in 2016. My father has cordial relationship with the tenant. Someone has advised him not to renew the rent agreement (on paper) and let the tenant continue to occupy the property. He has been told that the law is in favour of the landlord as such that the be property can vacated even with an agreement in place. I am not sure if this the right thing to do, especially since the property is in my mother's name who expired 7 years back. I need advise if this approach is detrimental for us and what could be the repercussions, if any.