Melissa's stuff is well worth checking out. I've worked with her and she's amazing. I don't think it will work fast enought to help him for right now though unless he gets a coach in front of him.
Singing is mostly psychological, so his comfort will make a huge difference. Any antagonism or pressure will most likely make things worse.
As far as mic cupping, depending on the model there are ways to do it without completely screwing the sound. You have to think it out and experiment though. You can't do it like most of these guys do with your hand almost completely covering the capsule. It's obnoxious and sounds terrible. A little bit of hand riding up the very rear of the basket is enough if you think it's needed.
Maybe same foam over the capsule and letting him hold it if it's a condenser could help him as well. If he's nervous though, your gonna hear it in his tone, and he's gonna probably push too hard and hurt himself as well.
That inhale pig scream is annoying. It can and has been used by others to a different effect though. Udo Dirkschneider from Accept has done it in a few places and made it sound pretty insane.
Try Fight it Back from Balls to the wall. The long scream at the end of the second chorus is an inhale.
Good luck with that recording, it can be tough. Try not to be too hard on him. Believe it or not getting him to run around the block can actually help! Getting a little exertion can help shake the nerves out and release some good endorphines, plus it will get him doing deeper, more supported breath. Shallow breathing is the first thing to happen when you get nervous and for intense vocals it's a garunteed stick in the spokes.
