I thought it was very good! Great that he is already composing at this age! Does he improvise?
Start with the left hand alone. Try to create a two-voice texture, with good contrapuntal independence. Gradually build the variety of character which the two voices are capable of channeling. Eventually the other hand will want to get involved naturally here and there in various ways. Best to stick with one hand for quite some time, studying the possibilities with which one hand can create the effect of two independent players.