Your friend's daughter needs medical attention on an urgent basis because of her temptation to eat chalk, rubber, pencil lead etc. Such a habit cannot be eliminated all of sudden but she can relinquish the same with a proper treatment. You can try the following points and surely she would be benifited with such a timely initiative. Here are a few points to curb this habit.
1) Your brother should talk with her daughter showing his full love and affection and taking her into confidence would ease the problem considerably. He should explain the entire side effects of ingestion of chalks, rubber and pencil lead etc. May be with the repeated counselling, she would relinquish this bad habit. Tell her seriously that this would affect her kidney because of presence of toxic substances in such items.
2) Take the help of psychiatry debuted in a reputed hospital and his counselling may run in multiple sessions to root out her habits. You need to resort to calmness during such follow us and surely she would get tremendous support by way of such counselling.
3) A prolonged intake of such toxic items could deplete her Homoglonobile- level needing immediate consultation with an experienced physician. He may prescribe Vitamin B 12 syrup or tablets apart from,an iron Tonic. If there exists an infection in the intestine, relevant treatment would follow.
4) Never allow her to remain in isolation for a prolonged time otherwise she would not in a position to give up this bad habit.
5) Encourage her to take Orange, Banana or some dry fruits like Walnuts, Almond, Raisins etc and such intakes of these nutrients may cause her aversion towards the consumption of such toxic materials.