Chad, I know how you love to play devil's advocate, but that is still a totally ridiculous thing to say. A contract between an employer and an employee is not the same as a contract between two private individuals. In the case of the former the balance of power is skewed sharply in favour of the employer.
I am not putting any opinion into this at all. The law is clear on the definition of AT WILL EMPLOYMENT. Unless he had a contract, and very few workers ever have a contract, he signed an AT WILL EMPLOYMENT agreement.
If you don't believe me, do a google on AT WILL EMPLOYMENT. Look at the papers you signed at your own job. They probably say something very similar to "employee can be terminated, with or without cause, at the discrection of employer at any time", somewhere after it says "employee can terminate employment at any time without reason".
Now, if he's Union, that's different, because the Union does have a contract with the company.