Mutual consent divorce

My brother is married for 2 years and 10 months(Feb 2013). They started having issues within one year of marriage. My sister in law has been too insecure when it comes to his friends. She also kept fighting with my mother on every small issue and asked my brother to separate from our parents. They have not had any sexual relationship for more than a year. They decided in 2014 to get divorced. However, my sister in law moved out in July 2015. Both of them earn decent. She has been an independent woman. however, she recently quit her job. We guess its beacuse she wants to prove that she cannot work and wants huge amount of alimony. she has started putting allegations on my brother of having extramarital affairs with multiple women. However, she doesn't have any proofs. I have certain questions: 1. For how long do they have to live separately before filing a mutual consent divorce? 2. How long does it take usually to get a divorce? 3. What are the expenses that would be incurred? 4. What should be the procedure that we should follow?