Skaz I think yours is a CRM problem that includes the management? You certainly have a problem that needs to be properly addressed and it shouldn't take an accident to do it. In the UK there is a confidential reporting system that is anonymous, does your aviation authority have such a system?
To what extent do captains interfere with your flying?
Onan the Clumsy Not sure how you tackle your problem. Possibly you could point out to him that if any kind of incident should occur, even totally unrelated, after he had touched the controls the witness statements from other passengers might cause your licencing authority to withdraw his licence to operate, either as an owner or a pilot?