Daughter - In - Law harass Father - in - law for property

Dear Sir, Need your advice on the following property matter. A father-in-law (84yrs.)owned 80 sq mt. banglow (on his wife's name). He is a sole owner of the whole house. He has 3 sons & 3 daughter (all married). All sons lived together. Out of which one of his younger son had died 3 yrs.back (his married life period was 15yrs. & he has 2 daughters. his married life was hell). Now, father-in-law wants his property to be shared within his children. Through gift deed he has gifted ground floor to one son & first floor to another son. Though his 3rd son (who expired) not has good harmony relation with his dad. That's why initially he offered 20 lacs to his widow daughter in law (as a share to her 2 daughters). The daughter in law is very cunning lady, having her business of garments & feeding their daughters'. But, that daughter-in-law dined to take an offered money and threaten the father-in-law to give her 1/3rd share in the property or else she could file false cases against him & his whole family. Due to which father-in-law file a Property Vacant Case against her. Still its proceedings are going on.....he has filed the case in May 2014. Against which that widow daughter in law did the following cases against him: 1. Taking help from some NGO - But after the discussion with party 1 (father - in-law) & Party 2 (widow daughter in law), The NGO backfired daughter-in-law and discarded all her allegations. 2. Maintenance Case in Family court - But after the discussion with party 1 (father - in-law) & Party 2 (widow daughter in law), the court verbally discarded all her false allegations but written declaration is awaited. 3. Put Domestic Violence Case against father-in-law & other members of the family. Who's proceedings are going on.... 4.Put case in Women Cell - it was also discarded. They favour father-in-law. 5. Put case in Some Women Commission - they also discarded all her false allegation & warned her to do all this in future. But despite of all the abovesaid, that widow daughter-in-law (who resides on the 2nd floor of the house) are doing amicably many bad/illegal things with whole family. She didn't allow to repair leakage seepage on the floor, due to which 1st floor residents are in danger etc....etc... My questions are: How long will we fight for the case??? How we stop her not to do illegal things in the house??? How we maintain our house if it get damage by her??? Police didn't help. Should we complaint MCD??? Does they help us to repair our house??? Also will tell you father-in-law already has registered will of captured 2nd floor. According to will no penny would be given to this daughter-in-law after father-in-law's death. Will be grateful, if you can spare some time to answer. Thnx & Rgds.