Thanks for the support all. I have been quite concerned about him. He was abandoned in an apartment building before I got him. It looks like he was fairly well looked after for a while but suffered neglect before complete abandonment. I am fortunate to have a great vet whom freely admits that she doesn't know all there is to know and seeks advise when out of her element. I also really appreciate the opinions I have found here it helps keep everything in perspective and make sure nothing is over looked.
Just a quick update in the last few days he has perked up quite a lot. I think the critical care is responsible as he is still not eating on his own. I put fresh greens in with him everyday and try to wait until noon before feeding the critical care to give him a chance to eat on his own. He has gained 38 grams in the last two weeks. I'll keep posting updates.
I am lucky she is a good vet. I don't expect he to know everything about everything and she freely admits she does not and listens very closely to my thoughts and opinions. To my mind this is the mark of a good vet (doctor... period!)