Live in one unit - It's a great strategy when using a bank for financing as the down payment and interest rates are more favorable to owner occupants.  

I got the numbers from the previous owner who has been running it as an Airbnb.  

Alternatively, your sibling might use a 1031 exchange to defer taxes by reinvesting in like-kind properties, though this doesn't directly fund a primary residence.Other ideas include leveraging a HELOC on the rental properties for the down payment, taking out a 401(k) loan, structuring an owner-financed agreement, or a lease-to-own arrangement.

I'm guessing though that since the IRA owner isn't allowed to take out a salary, perhaps the SDIRA LLC will be required to hire employees? 

So the added cashflow to property owners it they are willing to become the developer and increase density that tactic could help more owners stay than could otherwise afford to stay. 

But for many people, it is one of a number of sources of deal flow, to add to MLS listings, wholesalers, direct owner outreach, auction, etc.Assuming you are specifically talking about sheriff auctions, just make sure you familiarize yourself with the general procedures for the auction.  

I got a hold of the owner by looking up his information on the county website.

Otherwise, you'll have to get tenant & owner manual opt-ins for everything with little, if any, control.

The owner is open to seller finance for us.

The owners at the time were directed to our Real Estate agent and she showed us the property as it was a good investment opportunity.How did you finance this deal?