No need to worry!! If you ask your child why are you doing the home work or writing exams, the common answer is "Else my teacher or my parents will scold me. That's why there is lack of drive as they never feel responsible for their own studies. Once they understand bigger purpose is very important, they get the drive for achievement in life.
Whole brain methodologies like mind mapping, strategies on spelling, picture diagrams, principles of super power memory, time management, goal setting will help your child to do better in their studies. Onlysuccess study skill training program http://www.onlysuccess.net/beachamp/index.php will help your child needs.