There could be many factors contributing to this problem. Make sure he is eating a well balanced diet; lack of essential nutrients could contribute to this problem. Avoid sugary snacks as this varies the blood sugar levels making concentration difficult. Make sure he is getting plenty of rest and sleep, lack thereof could make him too tired to concentrate. Speak to him to gauge whether he is bored with any subjects or school. This might be a key area to focus on to motivate him or stimulate a sense of interest. Maybe a school or a particular subject could be overwhelming him and he feels he cannot cope. Try and help in this area if he needs it to break down tasks and maybe get him into group study. Using a school counsellor would be useful if you suspect there is something worrying him. If he is plain bored, try and get him to make notes keeping him active during class.
Consider breathing exercises as it will help him bring awareness to this problem. Make sure he is getting plenty of exercise done in the course of the day. Getting him into a team sport will be useful. A useful supplement protocol would be taking Omega 3 essential fatty acids. Klamath Blue Green Algae will be excellent for him. Its a nutrient dense food supplement. DMAE is another useful supplement to consider improving concentration. For further advice please feel free to come and see me at our Cavendish Branch. Kind regards, Reena (Homeopath)