Why Pvt. Ltd Company Fire an employee without any Notice?

One Pvt. Ltd Company(Start-up) call a candidate for an Interview, Candidate gave Interview and got Selected. Before joining Company candidate got clearance about all Confusion like Job Security and others and company Gave Answer we want candidate who stay for long terms. Candidate Got Offer Latter by mail with their working Designation. Then Candidate join in the company and after 2 days company gave physical offer letter copy to candidate and got signature immediately while they worked. But Candidate noticed There is other designation in the offer letter apart from by mail. Candidate talked with company MD why this? So got replay keep it right now we will change it. Also not provided appointment letter to him. But within a 20 days Company MD tell him you are fired immediately ... just one region is your English is Indian. Candidate Argue against it and tell why you are talking about this at Interview time, apart from that interview taken in local language. Also When candidate talked about family responsibility which is on him. Company MD replied it's your problem. In this case how we can do against company.