My sister,s daughter is 15 years old, she is no maturiy, ane she is studying in ninth standard, she does no no anything, she could not read one word, she is scolding her mother in bad words, telling lot of lies and come to house lately and she told reason my chapel is tear or my dress is tear and also school teacher told that please get her tc, she is not response any teacher. She is father deases in 3 years ago. Now i am guardian of her. I dont know what to do? Please advise me