Hello moms/breastfeeding mothers!?

Hello moms/breastfeeding mothers! ? My sister has been experiencing nausea for 3-4 months and her stomach hurts. They prescribed some medication (like Creon) at the clinic, but it's not working. She's tried different herbs as well. But everything is useless. She cries at night because of the nausea. We have visited several gastroenterologists. It only starts at night. She's already like a skeleton, she's losing weight every day. We're worried, nobody can help us. Has anyone experienced this before? What would you recommend?