Next, demands sex in a private office or she will terminate his job, all within the next few days from that very same employee.
If the employer has at least 15 employees, that would be sexual harassment, and illegal under federal law and the laws of many states. The male employee ought to report that to the offending manager's supervisors or other appropriate persons in the company. The employer has a responsibility under the law to make the harassment stop, and the employer may be liable to the employee if it fails to the stop the sexual harassment.
However, what you described is not criminal rape in any state I'm famailiar with. Since you didn't mention the state, however, I can't say for sure there isn't some sexual offense committed here.
Just to add a bit of spice to the situation, the said manager, a woman is a North Indian Hindu with strong religious beliefs and the said male is a non-businessman caste raised Hindu outcast so to speak, whom embraces the freedoms of modern India, also the male is an American citizen, the manager is not.
If this is taking place in the U.S., none of that is relevant to the issue of whether sexual harassment or rape occurred.