Take her to the doctor if you're concerned!
My daughter is 15 yrs old now. She is just 45 kg and nearly 150 cm . She doesnt have proper food since she is in hostel . Im very worried about her health .How to gain weight and height ? Thankuh .. waiting for a answer !!!
Just make sure she gets the right foods in her body and she will be fine
Take your minor child home and love her as best you can. Feed her yourself. At age 15, she is still your responsibility. If she needs mental health support and/or medication, get it for her.