We are indeed what we eat. I'm glad to read this update, I think you are absolutely on the right track! If anything, he should feel a fair amount better physically during this ordeal. The main takeaway in a lot of these is that our body didn't have what it needed to destroy the cells the way it normally does because it was fighting elsewhere the effects of eating bad things. We aren't perfect ourselves but when we eat really clean and don't cheat, we feel loads better and lose a fair amount of weight (we aren't heavy but we aren't as thin as we used to be).
Look forward to reading more updates, I'm rooting for you!