Intimidating to commit suicide

Dear Sir. My daughter in law namely Sangita Bhalla is living separately with her husband Vishal Bhalla for last six year. We have no interference in their life and have any business with them except my son sometime brings my two grand-daughter at my residence to meet. I never ever visited their house since their separation from us. Before their separation ,my daughter in law was Intimidating us to commit suicide and now she is in often Intimidate her husband in small issues apart from loose talk, shouting loudly , manhandling and quarrel. We are Senior Citizen of 63+ and wish to live peacefully but all in vain. Kindly guide me how to protect ourselves from her Intimidating to my son which is increasing day by day. Regard Ashwani Kumar Bhalla Asst Director (Retd)