Actually, it is Ling who is crying. Although it was hard to tell but if you really think about it, it only makes sense that Ling is the one that is crying. He's the one that knew Fu all his life. Plus, in the anime you could hear Ling's voice shouting while crying stead of Greed's.
Actually Wrath is quite awesome!! I loved him at begining of manga, and I love how he is such a huge badass and only ling/greed can battle him 4 times and still survive~(except the defeat of the first Greed)