16 years old boy suffering from mind fogginess memory and concentration problems sleepy during the day restless at night.magnesium deficiency ?

Foggy mind: Magnesium deficiency can present with such symptoms but also muscle spasms & cramps. I recommend workup by his Pediatrician to rule out other medical causes.

Unlikely: The fogginess is more likely due to a sleep disorder/inadequacy than an isolated magnesium issue. He needs to get at least 9 hrs of restful sleep at night and more if playing sports or studying or this would be the expected outcome. He may need a doc visit to exclude other issues that would interfere with his sleep pattern.