1. Know that to disown a son is not always easy, certainly not as simple as divorcing a spouse by him. Although divorce is never easy and brings with it its own set of issues, it is harder to disown another member of your family who is causing you trouble or heartache. Prepare yourself mentally and emotionally for a battle. To disown a son, no matter if it is figuratively or in a court of law, is going to be traumatic.
2. I can see the senior citizens are slowly trying to separate themselves from the source of the strife.
3. Hire an Advocate via reference or search one from vast database in LCI and file a Domestic Violence Complaint making son as respondent along with daughter-in-law as respondent and pray for immediate relief by way of "restraining order". Now if the relationship is especially toxic and they feel threatened, a restraining order will serve notice legally to the son read with daughter in law that senior citizen parents want no contact with both of them. This works wonders if property is registered in senior citizens name and have traumatized by greedy son read with coaxing and cajoling daughter in law.
4. After filing before the Magistrate directly the Domestic Violence Act complaint when they go before a Magistrate in a court of law and request an "restraining order" the natural relief other than "restraining order passed" would also be that of "disownment" too which later be filed by an Affidavit via two Newspaper Advertisements. Once this effectuated son and his men and agents including daughter in law will have no rights over residential property of senior citizens read with her right to residence will also be evicted. The restraining order is served via SHO local police station and violation of the same is strictly punishable and I keep my doubts if they can ever violate such serious restrainments legally obtained by senior citizens.
5. Gone are the days such as say 5 - 6 years back when via a simple template "disownement advertisement in two news papers" used to set the ball of eviction of son and daughter in laws work out, but today without a court Order served via local Police to them as suggested above neither will move an inch from your lawful properties. So this phase ball is in your court see to it that without shame and emotions read with parental sentiments if you want your leftover life lead in peace seek a just "restraining order" using Domestic Violence Act which one gets in under 60 days.
One can understand that it is hard to disown your won flush and blood who is your own child, but when you have tried everything and nothing has worked, maybe that son needs to be on his own now that he has been given education, taught how to stand on his own feet and later married off to person of his choice and agreement.
In nutshell it is doable remedy and usage of Domestic Violence Act is meant for this very specific purpose for giving peace to all those senior citizens by law of the land who want to live peacefully in their own hard earned saved properties without much interference of daughter in law and her husband who in instance facts happens to be your own adult son.