There is also stuff here at PC about bipolar and it's symptoms that you could print out and give him. It might be less overwhelming than a book on it.

Also, it is in most good guys philosophy to "fix" whatever problem their mate has. So his saying that he is your T doesn't disturb me. It shows he wants to help you. BUT you need to re-educate him that in helping you he needs to "support" not "fix".