My mrs has hyperemisis , how long will the not being able to eat anything last? and is the baby safe with just llittle bits of water at 7 weeks?

Until 12-16 weeks?: Nausea and vomiting of pregnancy are unfortunately very common and sometimes can be severe with hyperemesis gravidarum. Small, frequent snacks, avoidance of irritating foods (e.g. Fried, fatty/spicy meals, chocolate, cooked tomato), medications (reglan, phenergan, (promethazine) vitamin b6, zofran) and ginger snacks can all help. Maintain hydration and be patient; it is definitely worth it! baby should be fine.