Me thinks you are going to hard on him! Clearly he is a rookie, and a young one at that. Still, one way or another, he came out on the right side of this issue and he deserves credit for it.

He's not ready to be a leader yet and that's just fine for now.
This doesn't make sense. If he were a "sock-puppet" he would have voted No. While this one vote isn't conclusive, either about Efren or the project, it is a step in the right direction.
Even if your are suspicious of his loyalties, I suggest it is wiser to warmly receive this vote and hope, publicly, that it is indicative of his sensibilities, rather than to condemn him for it. Show him some love in hopes that he will feel vindicated and supported and will continue in this direction. You can always trash him later if needed.
To get elected or re-elected you have to be in somebodies pocket (ie be supported by a large contingent). Let's let him know that we stand ready to support him if he is aligned with our interests, so he can safely make the switch, if in fact your analysis is correct.
It will be interesting to see what happens if the project returns to board.
Remember Efren is young and new to politics. I met him and my sense is that he has a good heart. It's going to take a little while for him to find his path and to see which way the winds blow and how he feels about it. It's way too early to condemn him. And, so far so good!