There seems to be nothing on him in Greek on the web, the only mentions I can find are in English, so they're probably ones you found already. Someone on Twitter said he's still in Greece.
Considering the state of the Greek economy, I perceive he’s living “off the grid” like a king. With decades behind him, he likely won by remaining invisible.
By chance could you see if there's anything on his son? Eleuthertos George Veliotis