I am able to understand what u must b going through. Not studying is the main problem that might b visible to u. But there might b underlying reasons for this like attention deficit hyperactivity disorder, dyslexia, intellectual disability etc. Ur child needs to be evaluated by a psychiatrist. If u want to know any further details abt these things or clarifications u can consult me online through the Practo chat option. Best wishes for his speedy recovery!!