First of all, what happened to the complaint you have lodged with the Police? If no action is taken, approach the Jurisdictional Magistrate under Section 156(3) CrPC. In case your father had recived medical treatment and you have records of the same, it will help your cause,
As regards to their compalint, meet the issues on merit if you recive summons from the Court. Once you recive the copy of the charge report, you can weigh the option of approaching the High Court under Section 482 CrPC.