Nice find!
The man is an interesting character, a lot brighter than Mick, even with whatever has gone up his veins and nose. More power to him. Go Keith, go. You can do Mick, too.
If you haven't seen Charlie is My Darling, you should. There is a very shy "gosh gee whiz" kid there who has trouble looking at the camera and turns his back to the audience when on stage. Mick's ego by contrast is already huge. The writing of songs, as is documented by the film at least in its very limited way, seems to be that Keith comes up with all the ideas, Mick says what he doesn't like, and Keith changes things.