Your friends carried no insurance on the house? Even if paid for, they would be responsible if something terrible had happened, like carbon-monoxide poisoning, fire, someone got hurt on premises...the list is endless. Always, always have insurance. We carry an umbrella policy for $1 million and it "travels" with us, cars, house, etc....I believe we pay less than 200 a year for this, and are increasing it this year. See if your friends homeowner policy (for the house they live in) extends to any properties they own. Plus, if they bought the house, even at auction, there must have been before pictures....plus a written lease. Never-the-less, we have actually built our homes (took a course years ago) but some things I won't do-anything to do with gas or furnace. (Ok replacing water heaters, etc.) but not the main furnace, unless you have experience. Also, your friends really can't blame anyone but themselves, they didn't protect their property. For rent of $250 for a home, well it had to be in pretty bad shape to begin with. I would check at Habitat and also in the papers for some odd lot items, sounds like a small home, so flooring you should be able to get from Home Depot or Lowes, remnants dept. Watch paper for used fridge, oven, etc. for people doing remodels & upgrading. What happened to the appliances, or was the house condemned prior to the tenants? Did they just take the toilet, tub, etc? Why do you need plywood? For the roof? Or, are the floors rotten? I would def. invest in an alarm system, fence, and dog for inside if your FIL needs to camp out there, it's not just the people who lived there that he's worried about. Plus, didn't anyone go over occasionally to check on the property? Hmmmm.