allege and attack on my father who is of age on 65

hello sir, I am from Kolkata. Sir a recent incident happened in our building. My father was punched by one of the flat owners in a meeting. As my father protested against some of them as they always does work without our concern then demands money. They have formed a group and claims themselves majority and we are bound to abide by their decisions.In an argument they threatened my father telling that they will complain to police as my father is hampering the security of women leaving in our building which is clearly a political quote just to allege my father. This is not the first attack on him as previously in the month of January another flat owner of that same group tried to press the neck of my father then he himself went to our neighbors gathering them and alleging my father that he is hampering their peace, and that he is mentally unfit so couldn't control himself and threatened us to give a joint petition against my father to police. On both the occasion my mom was present. Sir my father is an retired employee of defense undertaking and from the last attack he was injured on his chest. In such a situation what shall we do?? Shall we have to tolerate this as they have formed a group and majority?? At his age of 65 just because of he protested, he will be beaten up and threatened using the several laws in favor of women?? Please help us sir and I will be highly obliged to you.