Thanks I googled the picture and I know that much I sent my friend a few screenshots of my Google search. And a few questions seeing as he didn't ask any.
I have a couple of those. I am sure others will give better details, but here is a start: Kingdom of Macedon, Alexander the Great III - Heracles & Zeus Greek Tetradrachm
If it's genuine, as mentioned above, it's Alexander the Great, but not likely during his lifetime. These continued to be minted in various places for a very long time. A real expert could tell you where and more or less when. But I'd be very suspicious. Something about it, especially the edge, looks off to me. But, as I said, I'm no expert.
