Even my E-2's and E-3's have sent emails...and get a LOT of them. I find it IMPOSSIBLE to believe an O-6 doesn't use email.
Graham is in the Air Force Reserve, not the Air National Guard. Since 2004, he has done a few high profile, member of panel type jobs during his active duty stints. He is not a drilling Reservist, of that you can be sure.
I’m sure that he gets assigned people who take care of whatever administrative requirements and tasks there may be.
When he was younger, and a full time Air Force officer, email was in its infancy. Only a few had it and certainly not the E-2s and E-3s. Your comments are correct in today’s military, but not the one Graham joined and his role in it today is more of a Visting Senator who is no doubt treated like minor royalty.