What about trying him on raw milk (if you can get it in your state)? Raw milk contains all the good enzymes and probiotics that are killed during pasteurization, plus all the good fat that is changed during homogenization. You can find more info about raw milk at Real Milk.
I'd definitely stay away from the soy - way too much controversy there for my taste. If he has a bad gut, have you joined the "Heal the Gut" thread? (I think it's in the Health and Healing forum.) They have tons of info on healing their dc's guts (and their own too).
I'd definitely stay away from the soy - way too much controversy there for my taste. If he has a bad gut, have you joined the "Heal the Gut" thread? (I think it's in the Health and Healing forum.) They have tons of info on healing their dc's guts (and their own too).