We had a similar issue with trains at that age. I learned to draw trains....
Sometimes, we drew what he asked. Other times, we'd paint a line and then he'd paint a line and go from there. We also just said no, I want to see your paintings sometimes. The alternating lines seemed to help. It also helped that my lines weren't any better than his usually. Neither one of us is an artist
Part of it could be that he sees a picture in his head much more clearly than he can reproduce it. It is a bit like early reading. He could read the same things, I jsut coudl do it faster....
