Michael Cudlitz’ comments at the recent Walker Stalker Con (via ComicBook.com) that Abraham wouldn’t be surprised that Eugene is sticking with whoever will keep him alive for the time being don’t reflect well on Eugene, but they definitely make sense with what we know of him.
He’s not a leader or a fighter, but he’s intelligent, and that has helped him make the right kind of alliances so far.
Despite the fact that Eugene has relatively limited survival skills in the zombie apocalypse, he’s a pretty consummate survivor by this point.
He has mastered the art of latching on to the biggest and most powerful person who could possibly protect him, no matter who he betrays and what the long-term consequences may be.