Once upon a time, my grandmother told me that tea and saltine crackers are the only foods that you can keep down when you have nausea to the point of vomiting.
Broths seem to work for me myself, like chicken broth or miso soup broth.
Also, I found this website that I think may be of use to you:
When you have nausea and vomiting: MedlinePlus Medical Encyclopedia
Perhaps if your doctor is unwilling to prescribe outpatient medications for alcohol withdrawal perhaps he will prescribe some anti-nausea medication instead?