First of all, FOR YOU AND ALL PARENTS OUT THERE YOU CHILD SHOULD BE SCREENED BY A PEDIATRICIAN OR SEEN BY AN OPTOMETRIST OR OPHTHALMOLOGIST BETWEENAGE 3 AND 4 TO DETECT POOR VISION IN ONE EYE (AMBLYOPIA).
The problem is likely that the vision in the LE is subnormal and won't come up even with glasses (aneisometropic amblyopia). He likely will need a trial of patching the RE to bring LE vision up. That is both difficult and at his age low success. He should be under the care of a pediatric ophthalmologist. If you have other children check them for the same problem.
How many hours a day he needs patching of the eye. is there any other solution or exercise. please let me know. sir.
We cannot answer these questions. They have to be by the ophthalmologist caring for your child. Please re-read my original comments.