Divorce before 6 months

I am asking a question for my brother. He got married in June 2017, this was an arranged marriage where my brother and his wife both met for the first time in April and then on mutual consent and with family's approval decided to marry. There was no force from either side to get married. I am his elder brother and a NRI and my wish was that they get married in November/December as that's when I can come to attend his marriage as I had some visa issues and it was difficult to travel with my newborn son. But the girl side wanted them to get married sooner as they had some family wedding in November, so we went by their words. The girl's family was very poor so it was me who funded the entire marriage which costed around 6.5 Lakhs and we also gave 2 Lakhs worth of gold to the girl. The girl came to our home and she stayed comfortably where ours is a joint family, which includes Uncle/Aunt, my brother and my mother (my father is deceased). After 15 days the girl started sleeping separately and she started quarreling with everyone and even with our relatives. After second month she left our home and did not come back for two months and she always traded insult to my mother. We requested a lot to come back and she said that she will come back if she stays separately with my brother. The other day she said that she needs monthly maintenance of 8000 and will not come back. She also asked for divorce from my brother once and has mostly been disrespecting him. My brother tried contacting her hundreds of times and she will not accept or return the call. So there was this weirdness going on for 2 months. One sudden day she came to our home and occupied a room and threw away my father's picture from the wall and throwed all clothes out and occupied the room. We are not sure of her intention yet as what does she needs, she hasn't talked with my brother and she probably has taken a job and works somewhere and we don't know where, she eats out and sleeps alone. All she does is come home at night and goes early morning, we are not sure what wrong we have done and what are her intentions. All we can think is that divorce should be taken if it goes this way. I also have the following questions: 1. Can the divorce be taken before six months? 2. It seems that the law is in favour of girl mostly, how should we approach court if we decide to get divorce? 3. We are not sure why she has come back after 2 months, is that something that she has talked with a lawyer who is advising all this to her, is there something that we are missing in her intentions as per law? 4. What happens that we want a divorce, do we need to pay alimony, if so how much?