2013's block reward is 25BTC actually.

But I highly doubt that he'd solo mined at that time, CPUs or even GPUs are getting behind FPGAs and the first generation of ASICs at that time.
It could be no-account pool mining that rewards their share to the specified worker address or a pool with account feature and his bitcoins is in that pool all along.

@megamarclar Does your "15eax" address have a balance when you pasted it in a blockexplorer?
Also, if you happened to do solo mining, there's a slightly long orphaned chain at that time and hopefully, your node (v0.8.0) isn't one of those that's relaying that chain and got rewarded from any of those blocks.