Would he be in for an experiment? Get a new blue t-shirt and (shameless extravagance) a new not-blue shirt and get him to wear both and see if there is a difference?
As a kid i couldn't differentiate between reality and fantasy at all, and found a lot of stories upsetting. And the music that came with TV, etc made it much worse. I think it's about not being in control - if he had a thomas dvd and a remote and could pause it to take a deep breath when something might be going to happen, or to fast forward the fat controller being angry then he'd probably be OK, but he's smart enough to know it's coming and not quite smart enough to know that it's a kids' story so it will always work out OK in the end....