Property Management- Family Business

Hi Searchers!

An opportunity has come up with my family's property management and brokerage business. as my father wants to retire. The good news is it's a great opportunity, bad news is, I don't think the owner has a good sense of the value. which is making negotiations difficult.

Anyone on here have an idea of multiples & valuation for a prop management business, separating brokerage revenue from prop management revenue and or has experience with inheriting/partial buy out with family businesses?