Divorse for sister, as she was totured by husband

hi, am in chennai. pls help in following.. my sister was married to person who works in dubai.. we trusted him and family and married our sister. marriage happened feb 2016, after marriage she done her mba at our parents home, and she left to dubai nov 2016.. we felt something is not right there, whenever she called via phone to india. 2 months after she came alone to india for my mother birthday.. but she didnt go back and saying that she was not happy. so we didnt send her and stayed for 8months here.. past 8months she was not good, everytime sad and crying. we dont no what to do. and we heard that her husband came to india 2 times, but didnt came to meet us .. even their family members didnt came to call/came to our home for this issue.. recently, we heard from office members of husband, that he was saying to all that he is divorsed and my sister character is not good.. so hearing this, my sister said everything that happend there in dubai during 2months.. she was totured mentally and s*xualy. she was isolated in home with no outside contacts. his friends were not behaving properly. she was waiting to escape from there, and got chance came by safely.. Now what can v do... he seems pysco.. my sister wants divorse.. pls help me.. how can i proceed ? we have never went to advocate before, so dnt no how much they charge approxi. how long divorse case usually take or can it be done soon with 3months..