Divorce in case of NRI spouse

My brother works in USA Texas as a research fellow and he got married in October 2016. His wife stayed with our family in India for about 2months while my brother went back to Texas for job. We sent her to USA in December and she stayed there for only 25 days she didn't even talk to my brother during this period she lived there just like a tourist and came back to India in January saying that she is not interested in staying there anymore.We have doubts about her conduct due to certain circumstances and her suspicious behavior.After coming back to India she didn't even contact us or my brother.Her age is 26 and my brother is 31 years old. She is teacher by profession.Our relatives are suggesting that we shouldn't continue this marriage as she is not really serious about this,and she will ruin my brother's research career if we continue with this marriage.Her intention seems like to extract money from us.What are the legal aspects in this case,if we want to take divorce,and how much maintenance she can claim from us.My brother's salary is $3200/month. Please guide what should we do in this case.