This really needs the second half of the story before we all get our trusty pitchforks and start making a shish-kebab from this Khan person.
Any large company is going to have abusive individuals in it. I think the real issue this story illustrates is that when people are brought over on work visas they have no leverage with their employer.
As an American citizen software engineer my boss knows that if I'm unhappy I will just leave. But the boss of someone on a work visa knows they can do pretty much whatever they want to them and the employee is just stuck.
So we need to change the work visa system so those employees aren't in such a vulnerable position. How exactly? I don't know..