Cockatiel stepped on, not digesting food?

On saturday evening, my mom (a heavy woman) stepped on my cockatiel Sunny (almost 3 years old, pretty healthy, some discolored droppings now and then). We took him to the emergency vet, where they gave us antibiotics and saline for a large cut under his right wing. Monday morning, we took him to a regular vet, where his cut was sewn up, and yesterday he was acting mostly normal, except a little clingy, and off-balance because of the cone they had to put on his head. His dropping have been discolored since he was stepped on. A dark green liquid with a tiny white cap, turning into more yellow-tinted urine with no feces, until today he dropped a dark green liquid with all the bits of millet he had eaten recently. I'm hoping desperately that this is just a result of the trauma, but I'm afraid there's something more serious wrong. My mom and I are going to consult the vet shortly, but I was wondering if anyone had any idea what it could be? He's on two different medications right now, medicam and an antibiotic. Please help!!