While all branches have special forces, NONE of the military jobs are listed on your ID card. Can you imagine an Intel Specialist being captured, and his/her ID card proclaiming to the capturing party 'I HAVE A REALLY HIGH SECURITY CLEARANCE, AND I CAN TELL YOU WHAT WE KNOW ABOUT YOU!" We are all trained to provide name, rank, and serial number ONLY in the event of capture--why in the world would they put other information (besides DOB) on your ID card, particularly sensitive information like that?
Second, all active duty members are required to update their CAC card upon any change in rank. And as PPs have mentioned, expiration dates are not that far in the future; there is a hologram on the front; the photos are taken with a very small "webcam" type of camera in your local personnel office. These are nothing like portrait studios, don't have the flag background, and produce mildly crappy photos. The actual barcode is on the back, AND there is a goldish chip on the front that allows the computers to read the information contained on the card when you log into a government computer. This is true of all branches, active, reserves, and guard.
Also, ID cards are not "really" issued by the branch of service. They are issued by the Department of Defense, and have a place to denote the member's branch.
But the entirety of this thread will not be enough to convince CW's sister if she is really "in it." The easiest way to show her he is not who he says he is--he has access, on ANY military base ANYWHERE that has a computer, to his government email. Both DH and I have used our "official" government emails for various personal business; as long as it's not sensitive information or over-used, this is allowed and common. Have him send her an email directly from his government email, that she can then reply to and receive a response back. All military emails will be in the same format:
firstname.lastname@(name of base).(branch of service).mil So if someone named John Doe is in the Air Force and is stationed at Patrick AFB, their email will be
john.doe@patrick.af.mil The person's name, rank, and office symbol will also show up (at least DH's does when he emails me). There is ZERO reason why he should not be able to do this if he is legit (which I have no doubt he is NOT after that ridiculous image).