My PhD advisor is making my life hell.?

I'm currently doing my doctoral studies at one of the top engineering schools in the US. My advisor is a US citizen of Indian origin. His lab has over 80% Indian students and and the rest are Chinese including myself and some part-time American students. Everything was fine and under control until a year ago when my advisor started a software company and recruited people in our lab. He only asked foreign students like myself and said he could not pay us because we were not allowed to work for more than 20 hours per week on a student visa. He said he would pay us later and that this would be a great opportunity... might extend to a full-time job offer with sponsorship for a US visa. He went on to say that even if we say "No", we'd still have to help with research stuff in support of this commercial effort. And he said that if we don't join this effort, then we'd have to find a different thesis topic. I was already three years into my doctoral studies. I got scared and I was in majority... forced to join this commercial effort. Then, all sorts of problems started to emerge. He made our thesis work the lowest priority. He filled our schedules with this company work. He made us come to school every weekend. We wanted to submit papers to journals and conferences, but he left no time for us to do anything academic. Last one year was pure hell. We had to put in between 60 to 80 hours every week with no vacation time. He said regularly that he could not promise anything in writing because technically we were not supposed to work beyond 20 hours. Slowly, I became worried. I was moving further and further away from academic work. No publications. Nothing. Besides, with no promise of anything in writing, I had to completely rely on what he was saying... that he would pay us later. The problem is that he himself does not do much work. He only comes to some meetings and he'll either fall asleep or he only wants to hear that things are running fine and clients are satisfied. He's taking all the money right now. Recently he told each of us how much money we would be getting "later". I was literally shocked by this. He is giving each of us a small fraction of the company equity (less than 1%), and he plans to pay us less than half the average salary a fresh/new PhD graduate would get in our field, in industry. Some of us raised doubts and spoke to him only to learn that he is expecting us to join his company no matter what. He's reminded us that in case we decide to leave him, we would need to pick a different thesis topic not related to the research supporting this commercial product. All of us are four to five years into our doctoral studies. We are left with no choice. We are foreign students and we don't know where to go ask for help. This whole department and engineering college are full of Indian professors and they all know each other. I don't know what to do. One friend has decided to drop out of PhD program and just leave. I don't think I can do that... I don't want my four years of effort in graduate school to go into a waste bin. My parents will be devastated.