It doesn't matter if he said it was his or not or whether it was his or not. That's not how possession works. But you were lucky they dropped the charges. No it should not be an issue now with regard to your visa or US travel.
This likely isn't going to be a problem unless you somehow manage to be in a position to apply for US naturalization. Then, you'll have to do some explaining, but it shouldn't be much of an issue then either.

