Wife of Dead Tenant Claiming Commercial tenancy

Since 1994 we had given 4 rooms on first floor for residential use of one Policeman. He came to live with his wife and two kids. In 2008 tenant purchased Duplex Bungalow, Nearby. In January 2012 , we filed Eviction suit on Bonafide needs and also that he acquired alternate accommodation. We filed all papers of his property, and also our large family. In May 2012 Written statement filed by Tenant- admitted acquiring property. In June 2013, plaintiff evidence was submitted and was due for cross- examination. In July 2013, the original tenant suddenly died due to ill-ness. In August 2013, The Legal heirs brought on record. October 2013, Legal heirs - filed new Written statement and Claimed that- Their father was paying for residential use of property, but his wife was a separate tenant since 1994 and was paying additional rent for Commercial use of property. (false story). and claimed that the wife had oral agreement with plaintiff, and was paying separate rent for Commercial use. Current stage- Defendant Legal heirs- Have filed Evidence on affidavit. Not a single paper related to commercial rent or any commercial activity filed till date. My question- 1. How to deal with the false claim by wife and children of tenant that they have separate tenants than their father ? 2. Our apprehension is that - they will produce some false papers relating to fictitious commercial activity and damage our case. 3. The original tenant in his Ws no where mentioned about his wife being separate tenant. kindly suggest...