Pica is often linked to nutritional deficiencies, particularly iron or zinc. I recommend asking your paediatrician for a blood test to check his levels; simple supplements like ferrous sulfate or zinc can often resolve this behaviour. Since he is also struggling academically, it is important to evaluate him for underlying behavioural conditions like ADHD. If diagnosed, behavioural therapy or generic medications such as methylphenidate can significantly help improve both his focus and the pica behaviour. Please consult a developmental paediatrician to tailor a safe and effective plan for him.