What would you have done?

It's apparent to me that a lot of people are thinking way too much into this.
The house was bought as is where is, and that includes the contents and condition....good or bad.
If the new owner would have came back to the old owner's family with a problem he found after the transaction (example: mold, cracked foundation, insect infestation etc.)
the chances are that they wouldn't have given a partial refund on the agreed price at sale. Caveat Emptor. Buyer beware. You buy it, you get it good or bad. Both parties made a decision to buy/sell as is.
What if the money wasn't found for 10 years? Statute of limitations?
In my opinion, there was no obligation on both parties after the sale stipulated, so the new owner owns the money fair and square.
What he decided to do with the money is his own business, it's got nothing to do with morality or karma.
So he decided to give it back to the family without even a thank you. What did that teach his kids?
It goes to show you what the old owners really care about morality and fairness, doesn't it?
I would have kept the money and gave some to charity, at least they would appreciate it. But that's me.
Just my $44,999.98 plus 2 cents worth.
Tom.