Try
1. Small frequent meals, no force feeding, just as tolerated. Eat food that is less odourous, not spicy, no garlic/onion/spices etc.

2. Drink lots of fluid, keep her well hydrated. Try energy drinks or glucose powder if needed. Its important to keep the fluids up, otherwise she will get dehydrated and have to be admitted to hospital for intravenous fluid.

3. Ginger tea, vitamin b12 may or may not help. Worth giving a try.

4. See your doctor and get some professional advice, if its still ongoing she might have to try some medication ie maxolon/ metoclopramide.

Its difficult isnt it. My wife is 12 wks pregnant, she had similar symptoms as well, sensitive to smell, frequent nausea and vomiting, but thank goodness she is feeling better gradually, hopefully it will completely resolve after 1st trimester.