If an in-person visit is not feasible, we can easily arrange video tours to accommodate your schedule.

You forgot one more thing, you're arranging the sale of real estate in expectation of a fee probably without a real estate license. 

Can you arrange for counters, floors, painting other “basics” without him tacking on his 20%?

I have the credit, experience and the knowledge on how to underwrite the deal to show their ROI in this arrangement vs a traditional sale. 

Friendship and business don’t always mix well, so it’s critical to use a solid lease and treat this as a business arrangement.

Sellers who are in financial distress or dealing with a property in poor condition might be more open to this type of arrangement if it helps them get back on their feet.The key to making this work is transparency and clear communication.

The fact that you profited from the arrangement over the 3 year option period ameliorates the "loss" you experienced on sale but I think you would agree with me that every dollar left on the table is better characterized as a loss than as a win.  

Another step is to ask your current lender if an expedited post-disaster inspection can be arranged to speed things up.

Your best first investment will always be your own living arrangement.  

I think this arrangement can suit both parties, he wasnt going to be able to keep the house but can still live there for super cheap.