421JAM
Tele-Afflicted
It’s unusual that this person calls it a D sharp. It IS a D sharp (and an E flat), but usually when you go down a half step you say flat rather than sharp, since sharp means UP a half step. So it makes better sense to call it a D sharp only if he was tuning up from D. As it is, he was tuning down from E, so E flat makes more sense.