I saw, in an article on "Halachic Considerations of Firing Employees" by Rav Dovid Grossman of The Bais HaVaad Halacha Center:
Hagaon Rav Moshe Feinstein Zt"l writes a tremendous chiddush in regards to firing employees who are not classified as an Ani. He writes, that any time a worker is hired without term, it is as if they were hired forever. Therefore, unless you cannot afford to keep them as employees, they are not qualified for the job, or another new cause exists making it impossible to keep the worker, the employer simply can never fire them. Consequently, even if the boss would like to take his relative into the business, or a more qualified replacement is found (assuming the current employee is also considered qualified, albeit not as qualified), the employee cannot be fired. Therefore, if the boss needs the work done, and this employee can effectively perform this work, he must be kept on the payroll. The Chazon Ish and others argue and allow a boss to fire any employee who is not under contract. Wherever possible, one should be Machmir like Rav Moshe Zt"l.
Is this prohibition actionable in Beit Din by someone who believes that he was unjustly fired by an employer who's also an observant Jew? How would one go about bringing such a case to Beit Din?
The type of case I have in mind: A person is being fired / demoted at the age of 66, one year away from retirement. This person has had no verbal or written reprimands, and, in fact, has received bonuses every year for good work. Both the employee and employer are observant Jews.