Best information I could provide without an inspection is to start by removing the source of the odor, which is carpet, padding, and fecal matter. Then disinfect the entire room. If the walls are permeable you may need to remove them. If you intend to leave flooring in pace it is recommended to seal the flooring to prevent odors returning in high temperature seasons such as summer.
Last step is to run Ozone for minimum 2-3 days
At the end of the day, and if you have the option m, you need to weigh the cost to clean or replace.
You will need to contact a company such as Restoration Management Company, who specializein Biohazard cleaning among other things. Don’t call a maid service or contractor to save money, they are not certified to handle these types of losses and you would be creating a liability for you and/or the owner.
Hope this helps!