No apologies needed for the tough love.   

The property sat on the market for a month before an offer came in, but the buyer backed out at closing.

I don't see any sense of urgency from you, so no one adjudicating this case would either, or end up taking any action!

Can fix the water damage in the basement yourself.

I am in the Clearwater beach Florida area!

Also go through a servicing company for payments to the seller, escrow can probably help you out with a recommendation for that. 

Bit of a long story, but my partner and I are trying to purchase a property from a family friend of mine and we're having trouble locating the last seller.

Quote from @Nicole Laba: I work with investors in Chicago who are actively buying off-market properties, and Ive noticed that everyone has a different approach when it comes to sourcing deals.

So if I do a good analysis of the property (including all the costs) and the property generates monthly CF with a DSCR above 1.1, I would be removing a big risk because the numbers add up.

Walking through, I can see that owner is the type that spares little expense with his own properties.