Making false allegations of threat is clear case of defamation. File a private complain in the Court of District and Sessions Judge as the offence is not cognizable police have no power to accept complaint. Punishment is 2 years jail. Complaint is to be filed under Section 500 of Indian Penal Code, 1860 enclosing list of witnesses. After filing of complaint Court will examine the complainant and summons will be issued to the accused. Defamation can be proved through witnesses who saw and heard the accused making defamatory statements. A complaint can be filed by father, relative or you can also file complaint through GPA. Draft GPA in favor you relative on 100 rupees bond paper or even on white paper take SPA to Indian consulate and get it attested which they will readily do. Now due to pandemic walk-ins to consulate are suspended you get attestation online. Send that SPA to your named relative he can appoint lawyer and file a complaint in the Court.