The ATF gets noting just by adding him to your trust.
If you do any future NFA transfers or Form 1 submissions, then at that time you'll send them the updated trust documents that list him as being on it, and he would at that time have to do a responsible person questionnaire and the photo and fingerprints and all that.
But until you do another for submission like that for an NFA item, you don't send anything new to the ATF at all.