Caretaker unwilling to return my flat keys to me as a owner.

I have a vacant flat in Rajkot (Gujarat), which is legally in my name as sole owner. Now, I permanently reside in Assam and rarely visit Rajkot. The keys of my flat, as a caretaker, has always been with my brother in Rajkot. I do not have keys of my flat in Rajkot. My brother has his own flat in Rajkot in which he resides. Now, my brother does not want to return my flat keys and has threatened me via whatsapp message of going legal, if I enter my own flat if I get duplicate keys of my own flat made. I have requested him several times via Whatsapp message to return my flat keys, but he does not cooperate. Secondly, my brother has never given me a hard copy of Will of my late father, despite several verbal requests. My father gave him the original Will, which is a registered Will, and I am also a stakeholder in it. I request for legal advice, as to what should I do legally to get the keys of my flat from my brother as a caretaker and a copy of my Late Fathers Will. Thank you with Kind Regards.