Suggest Remedy For Excessive Weight Loss

My daughter, age 33 and mother of 2 small children, has severe weight loss. Only meds I know She is taking is antidepressant and birth control. I receive many calls from family members to say how concerned they are. Daughter doesn't seem concerned but finally agreed to go to her Doctor, who only said she is still within range on the charts. This does not seem possible, she is so severely thin. I watch closely whenever possible and I don't see any other signs of anorexia. I don't know what to do, but she seems to be wasting away with sunken in cheeks and eyes, boney limbs, etc. I am frightened and don't know what to do.