Help, how would you structure this deal?

Multi faimily unit for sale, 270,000, annual rental income 37,000, annual exp 9,000.
I have cash for 20% down, but want to keep it for working capital, have helc that charges 8.99% apr. I have a relative that I know has around 90,000 in numerous cd’s, what are some different ways to structure a deal where I am putting the least out of my pocket, possibly doing something with my relative? I am wanting this property for income. Thanks for any help