I hope they do a full history and ask questions. They should do a physical and ask him to do things like squat (in the Cushing's world, we can't do squat, as we say)... and check for hallmarks like the fat pads, stretch marks, hump and all the lovely things this disease does to us.
I suggest bringing in some pictures to show a progression - just a few - some doctors love this... but I have had some say, so, you got fat...
I usually (now) let the doctor run the show and see how it goes. I have had some ask more questions of my husband (how much do I eat, drink booze, do I do drugs - as my answers would obviously be LIES! LIES I tell you...) and then offer up things as I think they will be taken well. I have been called a liar for my food diary (my career was ethics and compliance - all this hurt a lot) and so I just had to learn to bite my tongue and cry later.
There are good doctors out there. Bring things but I suggest to let the doctor take the lead so they don't feel like you went on the internet and tried to self-diagnose or listened to a crazy person on a forum. :)
Good luck and I hope it goes really well! Post after the appt!
I swear that we will lose our minds if the endo says he's just depressed!