My daughter is 32 1/2 weeks pregnant and told me that she was vomiting this morning and it was green. Her husband called their OB and he told thme that she had the flu and she was vomiting amniotic fluid and it was the baby's way of fighting off the flu. Is this even possible? I thought the amniotic fluid was in the mother's womb not her stomach.

No, that's not possible. The amniotic fluid is protected within the uterus.

Vomiting "green" is usually what is called bile and is common in pregnancy.