I know that his coach and he are really secretive about their training, but surely someone has some insight as to what is going wrong.
He ran 4:03 mile a week or two ago and now he runs 3:45 for 1500.
Has he lowered his mileage?
Are the fast food rumors true (hopefully, that wouldn't affect him that much)?
Could it be that he is fatigued and needs a few weeks off that he never took after running the American record for the mile?
Could it be something that we don't even understand?