We had the same situation with our original bass player. We approached him as a band and told him that we felt it wasn't working out, as he wasn't up to playing the music we had picked. He agreed, and we parted ways as friends. Honesty is the best policy. As others have said, maybe he can be a better front if he puts the guitar down. Tough situation all around. I can say this.... every personnel change we made (there weren't many) over ten years made us a better band.