What rights does a employee have that has been placed on medical leave for anger management. His employer told him was fired, than after a meeting told him needed medical theropy for his issues and plaved him on medical leave. if he does not return to emp

My husband has had several accounts of anger issues at his work. The company he works for has no HR department and is a sawmill. All employees use harssing words toward each other and fits of anger are common amoung these employees. Recently his employer has called he in after a anger explosion and fired him claiming he can not be liable for him to be at is place of work. He than called a meeting and told my husband he was on medical leave. Now he is telling him he needs to get all his paperwork in order to be able to bring him back to work. What can my hasband do if they fire him?