Help/ Guide to tackle tricky situation created by my Son-in-Law.

I request you to give me some of your precious time in the below matter of my married elder daughter who is facing problems in her married life from last years. My wife and I are senior citizens, my wife is 62 and myself is 72 age , at this age. Your valuable advise will be helpful to me and guide me to take corrective action. 1.) My elder daughter was married on 05th March 2003.(Love Marriage ,Classmate, Same Caste :- Sindhi) 2.) My son-in-law is torturing and harassing my family, my elder daughter and his son who was born in the year 2007. 3.) He has got illicit (EXTRA –MARITAL AFFAIRS) relationship with a married woman whose has 2 sons.She stays in Dubai and comes to Mumbai for 3 months from June to August every year and meets my son-in law on daily basis near to his office. My son-in-law gives his girlfriend a plenty of expensive gifts and money with a debit card. This is happening since last 8 years but we have come to know only 3 years ago. 4.) He doesn’t have any meals i.e. breakfast, lunch, dinner with his son and my elder daughter and not also drink water also ,he brings bisleri cans in the house. 5.) He blocked all the mobile numbers of my elder daughter and as well as email ids so that she doesn’t communicate to him in anyways be it emergency. If there is an emergency she gives me a call. There was on instance my grandchild needed medical emergency she had called up her mother, sister and me. 6.) He DOES NOT AT ALL CONTRIBUTE A SINGLE PAISE EITHER ON HIS SON’S EDUCATION NOR IN HOUSEHOLD EXPENSES THROUGH HIS SALARY OF BEING ABOVE 5 LAKH PER MONTH .HIS LANDUARY (DHOBI) ,SOAP, TOOTHPASTE ETC I AM BUYING IT FROM DMART MULUND AND GIVING MY DAUGHTER . While on the hand my daughter earns rs 6000/- per month from her part time job. I have to support her financially by giving her minimum of rs 15000/- per month, also plus supporting her by supporting my elder daughter and grandchild by giving daily food items. 7.) My Grandchild school expenses from his school fees, bus fees, books and extra project material all these I need to support financially which sums to 1.8 lakh and increases every year by 10% to 15% My elder daughter and I had objected this extra –marital affair from long time, but my son-in-law is threatening my elder daughter that he will give her divorce and will throw her out of the house with her son and also without any compensation for my elder daughter and her son. Also this all my son-in-law‘s parents and his brother and brother’s wife as well his relatives is fully supporting him on having this extra –marital affair. I will be obliged if you can spare precious time to read the above matter and provide me with correct course of action can be taken by myself. As my daughter doesn’t have any money and nor time as from morning to night she handling her son sending him school , studies and household work .Would appreciate if you could provide any action can be taken by myself.