Company policy for termination differs from company to company. Also, you have not mentioned whether the boss is new. If yes, he can approach his superiors and sort out the matter. He can also state that he would not like to report to him in the future.
Check for Internal Job Posting (IJP)
Ask your husband to have all communication documented via emails. Even if his boss is not sending any emails, ask your husband to send emails so that he will have everything in a documented format.
These were the general suggestions. To assist you further, kindly post the exact situation. We, all Citehr Members, will be in a better position to help you.
Regards,
Sonali V. Neve