I thought bob was crying because he's an alcoholic, and he was drinking the wine. I remember last season he almost got someone killed for a drink.
Was Bob drinking for sure? I didn't notice a wine goblet. I did notice a definite change in him after being dragged down by the water logged zombie, so I assumed he had been munched on and didn't want to tell anyone. I think one of the other characters even asked him if he was okay (emotionally).