how to structure equity with first time home buyer live in PM

[Kristi Kandel]

Hi I own several rental properties and want to get my family involved. I have my eyes on a 4-plex where my brother and his wife would live in one of the units and we'd long term rent the other 3 units. He would be a first time home buyer and would get the 3% down. I would gift him the down payment so he could get the loan. They would essentially be the live in property managers but would be paying monthly rent.  I'm wondering how to structure his equity and what he needs to do to invest to eventually become a 50/50 partner. For round numbers let's say the down payment and closing costs are 20K at the 3% down and I put in the 20K. Should he automatically start with any equity? If they do the onsite property management for 8-12% of the monthly rental fee he could build up to his 10K in a few years. 

Or what ideas do you have for how to get him into his own real estate empire?