Hello and thank you for asking your question. My name isXXXXX will try to help.
So, the reason he vomits bile is that there is to much acid in his stomach and no food to absorb it. You can help reduce the acid by giving him a human stomach acid reducer such as Pepcid ac. Give 1/4 of a 10 mg tablet, per 5-15 pounds of dog, ever 12 hours. That should stop him from vomiting bile if he does not eat.
You can try giving him Pepcid for the next few days and see if he will eat the left over pieces, and not vomit bile, on that.
Since he will not eat it plain, and you can no talk to him and tell him he needs to eat all the pieces in the food, you will probably have to add a little something to it. You can try a tablespoon, or two of canned food, broth, or even water. Warming the food can help make it more fragrant, and appetizing, as well.
I hope this helps.
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