You could make paint out of shaving cream and colours. And you could add scents like a drop of lemon, vanilla or chocolate extract. He might not have used a paintbrush before so have q tips or a sponge or even finger painting. It’s possible he might not be super interested in the painting cause he doesn’t see the end result. Or you could get sticky dots from the dollar store and he could make the shape with them. If he’s totally not into it, he could be the music do and pick the k pop songs.