Even my sister was married to guy from her office. It is her fate and we have nothing to do with it. The guy belongs to another cast and they asked my uncle, but my uncle told my sister to give him some time. But then the guy was fast to do something which is to be done after marriage. SO, my sister had to marry him quickly.
Bhai, sit and think about your life, rather than feeling for your sister. Ultimately you will end up in a bad way if you think about your sister, like me. We can only show the water to a horse, we cannot make it drink the water forcefully. If we do so, we will be kicked out and the horse is always safe. So, don't be a horse. Be a Human and they will come to know the truth of life after some time.