Here's a breakdown on loan options to consider:FHA Loan: @Brittany Minocchi is right in looking at FHA option.  

I've also used traditional loans through regional banks and a few SBA loans. 

I can only imagine that they got a bunch of big time investors and business loans to grow this out.

For context, I will be assuming his VA loan at 5.1% and he will be doing seller financing for the remaining equity and sale price. 

Now my investor network as expanded and the best split I have experienced was 65/35 in my favor but I invested 40% of the cash and created over a million in imputed equity before any investor dollar was raised allowing me to originate a bank loan at 87% LTC.

You could get a loan from a local bank or private lender to fund it

Possibly using mortgage/home equity loan on one unit we own to buy an extra one.3.

If they have a good interest rate it might be worth looking to see if you could assume their loan to take advantage of the lower rate.  

Quote from @Guadalupe Batana: Learning about different types of loans is always a smart move, especially as an agent.

Did you use a hard money loan for this?