Yeah, he's fine. I just completely forgot about him. It's kind of like last season with the episode where John was looking for who killed the one ranger (the one we just found out that Virginia's sister killed). The woman they ultimately framed, I had completely forgotten who she was and had to look it up. They need to at least develop the character a bit if they want to use her for meaningful death. So far this half season, they definitely understand that.
Also, in talking about the rabbi, I recognize the actor from other roles (House), so I won't forget who he is.