Looking at this story purely in retrospect -—
He misjudged the homeowner’s fairness to reward his honesty with a decent share of the loot
Never in a zillion years would she have found the money by herself. The cash stash stayed in place until he started renovating
He should have kept the money and told no one not even his wife
He should have disposed of the currency at coin trading shops for cash. This old currency had numismatic value of upwards of a million?
Then to be fair once he got a good fix on how much the boodle was worth he should have left her with a paper bag full of cash. $100,000 on up. Had a courier deliver it anonymously or send it via UPS
We all know the outcome now— The homeowner’s greed landed this in the courts and both parties befitted minimally
It would make a great movie the way you play it out, that’s for sure....