Transition layer.
You would think that anybody competent enough to command a high performance turbo prop would also have the required CRM skills to be able to handle this situation in a professional manner.
A little chat to the CP himself about what is considered to be safe and in the confines of the operations manual is all that would be required. This is certainly what any competent pilot would do.
There are many good books on CRM and if you hold an Australian ATPL you might just find one in your collection.
If this does not help you then either-
A) You do not have the skills required to be in command (This takes more than just flying skills)
B) You are in need of a new CP and this will sort itself out very soon.
(I strongly believe option A is the case)
And lastly, your original post leaves two distinct possibilities as to the identity of this person. Do you not feel that you owe it to the CP you are not talking about, to make this clear. Again, very bad use of CRM and another reason that option A seems more likely.