Senior citizen herassment by Daughter in law

I Have realized an incident with one of my childhood neighbours family on ill treating a senior citizen women ,who is almost 70 years and was house arrested ,,being herassed with daughter in law. She is the wife of late district sub collectors for one of the district of Andhra Pradesh,Hence a pensioner of 25 000Rs/-.The son and daughter -in -law has forcefully taken her to the village where he works and is grabbing all her pension and not letting her move out of home.As per the neighbours she was beaten hard everyday and not in a position to move .Still they r making her to clean all the utensils and then only they are providing food. They stopped giving medicines for her parkinson desease.As they belongs to Schedule Tribe caste ,No one is in a position to go against them to report police (had chance of filing SC ST case in reverse)and also the old women is not willing to talk against her son in a assumption that he would lost his LIC job.She is having 3 daughters and 2 of the daughters is not interested in this matter as they are government employees and it could be a threat for their jobs.The third daughter would like to take her mother away and requesting her brother for the same .she is even requesting him to take the pension and leave her..Which she Could not succeed.Is there a way that this could be sorted out with the support of law without any damage to any individual with the SC ST Act.please suggest the ways to bring her out of that hell legally and save.