Mental pressure created by my younger brother's in law on my senior citizen parents.

My brother has abonded the social society due to his in laws cruelty i.e. on 20th december 2017 on the day of his girl childs 1st polio and other vaccines his father in law insulted him in the hospital premises infront of the public for a shortage of only 1000 rupees which my brother felt to be unnessecary for any type of dispute when he informed about the incident to my mother she called to his wife and talked to his mother in law and father in law about the matter and there was a slight arguement regading the matter but my brother took it heartly and decided not to visit his inlaws house ever again but on 21st december, 2017 his wife visited our house around 3 p.m leaving her 45 days old child at her parents home and fought with everyone and pressureized my brother to abonded his parents and to claim his part of property from my parents which my brother resisted to doing so, after which she tried to commit suicide by taking her fits medicine overdose she was hospitalized in that matter around 8 p.m on that very night around 11 p.m without informing anybody she moved out from the hospital with my brother to her home and later on 22nd my family went to police and filed an FIR about her suicide for property divide between our 3 brothers then his in laws started blackmailing to my brother to put him in jail if property not divide as soon as possible. On 22nd december 2017 around 8 a.m my brother and his wife with their child arrived at our residence without any information and they decided there infront of my parents that she will not commit the same suicide attempt or any type of disturbance inside the house ever again which was also recorded by the police on the same very day. but she never was commited to her words and from 24th december 2017 upto 10th january 2018 the whole family never able to sleep at night due to her unnesseccary arguments and asking for her husbands property again and again. Hence to stop this regular arguements and disputes my brother dropped his wife and child at her parents home and later abonded the social society by writting a letter to my father and to police that he is will fully and in presence of mind taking the step to abonded to everyone and never to return again. But now on 25th june 2018 my brothers in laws are putting mental pressure for to take back their daughter in law and her grand child with also forgetting every past matters let my brother present or not so what action can my parents take to avoid this daily situation and mental pressure from my brother's in law family as my parents are senior citizens please provide us some way to avoid this daily drama.