In WI, does a property manager have to be a licensed broker/salesperson? My parents own 12 buildings that I assist them with.

YES. Key components of property management (leasing and renting) are considered real estate activities under existing Wisconsin real estate licensing laws. If a property manager is going to negotiate, or offer to negotiate the rental of an interest in real estate, or promote the rental or leasing of real estate, he or she will need a broker's license. A salesperson working under a broker may engage in such activities.