How long will it take to get judgement from court if we file a case fo

We are a Hindu family. My wife and I got married in 2006 in the UK. She was a British citizen and I hold an Indian passport. I'm living and working in the UK currently. My wife passed away in 2021 due to a chronic disease. Last year the sole survivor from my wife's family, my father in law passed away too. He had a flat in S. Cruz west in Mumbai and bank savings along with a locker. He has a brother and a sister who are alive. My wife's mother and elder brother had passed away before I had met my wife. Some banks have me as nominee and some do not. As my father in law has not left a WilI and he does have a surviving brother and sister, I'd like to know what are my options for applying as a inheritor to his property and assets, according to the Indian laws. Is it wise to make a claim? What is the duration of these decisions in the Indian courts and what are the expense amount I will be looking at?