Reasonable expectations of a senior co-founder?
dhimes: I'm not sure I would discuss it unless it really gets in the way.  He may have picked you for a bright team member who can handle it-- and maybe you can.  When and if it starts to be a problem, that is, when you actually are sure you are not learning what you feel you should be from him and the project is suffering, then broach the subject with the CEO.  Perhaps the guy will come back when a need is demonstrated.If this business is a good opportunity for you, just hang tight.  The other guy could have the bigger problem anyway:  Your proximity to the CEO is going to make you very valuable to him if you end up being a reliable player.  The CTO may find himself out of the loop.