Thanks all for your responses.
I am not willing to give up yet, when my daughter was in daycare (for 5 months before I opened my own) she cried a lot too, she was terminated from her first daycare after 2 weeks. Her second daycare (while it was not ideal in some aspects) gave her more time and eventually she fit in and only cried for a few minutes at drop off. I feel like I definitely own this boy a chance like my daughter was given.
I only have two others in care plus my daughter, so the boy does get a lot of individual attention. We spend lots of time outdoors, lots of stories, circle time etc. I feel like if he is not happy here, in what I consider to be a pretty ideal situation,he won't be happy anywhere. I don't want to fail him if you know what I mean.

On the other hand, the crying sucks. Some days he does ok after a little bit and other days he just does not stop. He is happy (or at least quiet) when we are in the wagon, but that has been the only consistent thing that has made him happy. I told the mom today that we had a rough day, she seemed ready to cry. My heart is breaking for this kid and his mom. I really hope I can give him whatever it is he needs, and soon!