Protection of senior citizen from violence related to property dispute

My senior citizen father (79) and mother are second floor of a Delhi house. There is a court lawsuit related to probate currently going on. However the opposite party, who live on ground floor and first floor of the same house, are building unauthorized construction on the property, despite the ongoing court case. On Monday when my father protested against the construction, my cousin relative (45) pushed him violently and verbally threatened to kill my mother and father. I am quite scared of their safety, since I live and work in a different city and am unable to come to their aid immediately when such incidents happen. How can I protect my parents against such violence and threatening incidents?