This is very common because he is lacking the ability to stay focused and therefore becomes bored with activity and has a very physical need to change activities frequently and after very short term periods. I suggest you provide him with video games suitable for his age group. This is an amazing technique that encourages the mind to focus on many factors at one time, such as eye hand coordination. Allow him to play it as often as possible and I am sure you will see a difference in his abilities to stay focussed on one activity in a rather short term period. We went through the same thing with our son and the video games have and continue to be an excellent tool to train the mind to stay focussed on one activity for longer periods of time. Prayers and best wishes.