Technically, if we're going into full wish-thinking, that can happen to Eugeo too. There is therefore no actual evidence to support that he's not coming back, unless Reki himself says he's never coming back.

Is Eugeo coming back in unital ring?

No He Isn't!

Did Eugeo survive?

Eugeo and a heartbroken Kirito shared one last conversation, and as Kirito finally recalls his memories of Eugeo and Alice during his first dive into Underworld, Eugeo succumbed to his wounds and passed away in Kirito's arms.