Re: Tactful corrections of band members
Something else I just thought of that might be a tactful way of handling this comment (although be prepared for the consequences) is that when you suggest that he try something else, he gets annoyed, and says, "I don't tell you how to play", say something like, "I understand and basically agree with that approach. However, when one of us is playing something that you strongly feel does not work, I want you to say something about it, so at the very least, we can talk about it, explore what we each feel does and doesn't work about it, why we each feel it's either important to play that or try something else, etc. We need everyone to share their opinions about what everyone else is playing--both praise and constructive criticism, in order to make the band that much stronger".
I mentioned that I also have a lot of the "let's not tell each other how to play" approach in a situation like your band, but I think I'd respond well to what I just suggested.