If you are working at this facility you are a mandated report, meaning legally you MUST report abuse you see. Morally you must, as well. You will know the chain of command. Follow it to the top, put it in writing and let them know you need to know that this is being handled or you must go to the authorities to report an assault.
I am assuming Mom is in a facility, not your home.
I would have marched up to the Nurses desk and asked for the DON and reported it. That staff member should be fired and an incident report written up. If you r in an AL, he Nurse in charge. If after complaining and that staff member is still there, go to the Administrator. Even though ALs are privately owned, they are still inspected by the State.
If you witness someone physically abusing another human being what to do is pretty simple. Stop them from hitting the person if it's safe for you to do so and call the authorities. Physical assault is illegal in every state.
Per state regulations you are supposed to report it immediately to the DON or administrator. If you work evenings or nights when management isn't there, call the DON at home, or have the charge nurse call. The DON has to report this to state right away as this is the worst offense an employee can commit and it is taken very seriously. If you don't you can also be held responsible and fired. Since you didn't report it right away, report it NOW and let them know you just found out what you were supposed to do. It is the DON's responsibility to immediately remove that person from the floor and initiate an investigation to determine if the accusation is justified or not, as sometimes people are falsely accused by other staff or residents. The DON has 5 days to complete the investigation and submit a full report to the state. If the accusation is found to be justified the employee will be terminated, and possibly face criminal charges. If it is found to be unjustified the employee will be paid for their time off. Please don't be afraid to report this. Think how guilty you would feel if this person hurts or even kills somebody the next time, because there WILL ne a next time! You are the voice for the residents that no longer have one, and it is your duty to protect them and keep them safe.
I would have marched up to the Nurses desk and asked for the DON and reported it. That staff member should be fired and an incident report written up. If you r in an AL, he Nurse in charge. If after complaining and that staff member is still there, go to the Administrator. Even though ALs are privately owned, they are still inspected by the State.
I would also follow up with a letter.