A firefighter where I work in SC susposedly created a hostile work environment by sending an email to another employee. He is still unsure about any laws that he may be in trouble for as to the employee manual and policy and procedures book does not well define disiplinary action that can be given for his offence. Also, a couple of days later another employee had a worse violation as was given a less harsh disciplinary action. Does this firefighter have any recourse beside a written grievance that can be filled to change the diciplinary action taken against him?

Not unless such a recourse is provided him by contract.