Dear Concern,
Please note -
01. File an informatory application under section 39 of the CrPC before the District and Session Judge of the Pune. This application is filed to inform the court that someone is going to some crime and that someone shall be watched and if he or she does someone exactly matching to what has been apprehended as per this application then other people shall not be held responsible.
Since this is an informatory application so no notice will be issued to your father or any other member of the family and simultaneously if he actually do something then he will be held liable for it and no one else.
02. Secondly file an criminal complaint before the local police station of your residence by the way of post under section 506 of the IPC stating that your father is criminally intimating all of you or you (I mean sister - it is she who should do all the above and below mentioned activities on her name) of committing suicide and then implicating all of you or you in general. Keep the tracking report of this application with yourself.
Send similar application in SP office by the way of post and keep the tracking report of the same with yourself.
You are requested to do so that you can approach the court under section 156(3) of the CrPC to register an FIR in coming future if in reality your father does anything which he is saying.
Likewise above no intimation will be issued to anyone and you will be in safe situation if you have already undertaken these steps.
03. Thirdly if you want to safeguard your rights in the property owned by your father or the property which is coming to you from your ancestors (grandfather, grandmother, great-grandfather and great-grandmother and so on) then you should file a civil case of -
(a) partition for your ancestral properties,
(b) maintenance in against your father to compel him to bear expenses of your marriage as he is legally liable for the same as per the law, and
(c) suit for permanent possession and injunction in against all the self acquired properties of your father stating that he is trying to sold of his entire property under the influence of other unknown people. Do it on the name of other unknown people (marking them as friends, professional known and colleagues) so that no one gets entangled in this fight individually and it remains only in between you and your father.
Court will grant stay in your case and hopefully when your father will appear then he will settle this matter with you (I am telling you this as per my experience most of the time it happens in my experience).
My best wishes to you for your life and marriage.