Q: I am seeing someone who is employed by the college I study at, He is 21 and I am 18.

A: Employment in the U.S. is "at will," which means that the employer generally can fire an employee for any reason. "From a judicial perspective, the hallmark of at-will employment is that courts cannot review the employer’s decision to fire an employee. This is true because a court has nothing to review if an employer may fire an employee for any reason, even if that reason is irrational, or for no reason at all.

The first exception to the at-will rule was made in 1959 by a California court holding that an employee could not be fired for refusing to commit perjury on behalf of the company. Since then, courts and legislatures have carved out numerous exceptions to at-will employment.

In 1964, for example, Congress passed Title VII of the Civil Rights Act. This landmark law prohibits employers from discriminating against employees because of their race, color, religion, sex or national origin. Congress subsequently passed other laws prohibiting discrimination on the basis of religion, physical or mental disabilities, veteran status, genetic information or citizenship."

https://www.law360.com/employment/articles/851247/the-end-of-at-will-employment

What this means for your boyfriend is that the school could have its own internal policy that prohibits dating students. If he violated that policy, then the school could fire him. It is still worth seeing a lawyer, however, because they may not be applying the policy with an equal hand and violating a state or local law. Only a consultation with a lawyer will let you know if that argument could be made.

You also wrote that: "They are now discussing dismissing him and putting it on his record so he could never become a teacher . . . ." That result -- never becoming a teacher -- seems highly unlikely and that's another reason to talk with a lawyer about the situation. It may give you peace of mind.