@JD Martin I am particularly disturbed because this is a source of my parents retirement.

From what I've seen lately, the best price-performance mattress < $500 according to one of the few still indie review sites left (Consumer Reports) is the mattress hardly anyone's heard of: Sleep Innovations 10" Marley @ $275 (queen).

I took a trip out there a few weeks ago while it was vacant so I was able to get into the house without disturbing any tenants.  

I don't know how to address the mold issue, but I have a clause in my lease that basements are not to used for sleeping.

Because if they didn't have that optimism, they would probably be still on the sidelines.So it comes down to how well will you sleep knowing you are potentially out of pocket a large sum on a $250,000 house (replacement cost, or to put it more easily a mid-century ranch in middle america that has 2200 square feet).

One internet marketing program claims that you will make money while you sleep.

You may need to say you owner occupy the unit (no one checks maybe you sleep there sometimes haha) to get it approved.

Or should I let sleeping dogs lie until lease expiration? 

Obviously there was discussion and focus on the recent bank failures, as well as the debt ceiling.The response from management on the debt ceiling was "I'm not losing one second of sleep over it, IF there isn't an agreement in time then it will be resolved within days".

That's just my $0.02, but I value being able to sleep at night.