Uh.. There are finders rights and reasonable doubt.
Even under old English common law, finders rights would not have applied here. The finder can make a claim of ownership against anyone except the person who lost it. If the person who dropped the money is trying to recover it, then the finder has to return it. Even so, this isn't old England. Local laws apply and in most jurisdictions, found property must be turned over to the authorities to allow the original owner a chance to come claim it. After a certain time period, often thirty days, the finder can return and claim the item.
Much like many commenters, you might be thinking, if this man found a fairly small sum of abandoned cash on the ground, then it's no harm to keep it.
But, under Georgia Code § 16-8-6, "keeping property you know or learn is lost or mislaid without making reasonable efforts to return it to the owner is considered the criminal offense of theft of lost or mislaid property." In other words, Georgia does not take "finders keepers" as a sufficient answer to why someone might keep the money
