Cleaning the steps should not be a problem. I would use a good heavy duty stone cleaner and rinse with a pressure washer not greater than 300PSI. The problem I see is that the steps appear to be spalled. My guess would be from deicing salts if they are in a northern climate. If this is the case there is really no repair. I would just clean them and have them switch to a non spalling salt such as Potassium Chloride.