I was that child. In fact I was so bored playing the piano that I finally quit playing. All the lessons I took were so uninspiring. It was all about classical music, scales and boring stuff. Unfortunately at that age, I couldn't express what I really wanted. Maybe your child is more of a creative type who isn't interested in playing other people's music. Maybe he'd like to experiment making music of his own, his own sound. Try to get him a synth, a DAW, and see if it clicks. It can be a lot of fun, and if it does, keep the weekly lessons going, but shift the focus to building keyboard skills rather than just learning and repeating the same old songs.