You might be right about them having a bad day. Yet there is a large probability that they either: one, let it slip; two, lost it and forgot about it completely; or three, have a lot more money than you are use to.
There is also the large probability that they have a different perspective on money and manifestation than you.
Not everything that goes around, has to come around. You can learn this lesson from the bureaucrats that sit at the top of the money pyramid in this world. The 'trickle down effect' does not exist.
Anyways, thanks for sharing and in the future I suggest you add more to your story to make it an article and not just a blurb. What were you doing before you found the money? Or maybe you want to create a hypothetical reality of what happened to the other person after they lost their money and make it into an imaginative story.
All the best,
Monty