As a DM, it's quite possible he was pre-selected by Delta and will not need to enter a Known Traveler Number in his profile. If pre-selected, you just need to enter your name, gender and birthdate in your profile and check the box to allow Delta to share it with TSA. The OP should check his email to see if he's received any correspondence from Delta about it.
Thats how I did it as a Plat!