M.W.
I use disposables - but the first thing I thought of when I read your request was switch to cloth diapers. Anything made of natural fibers will help his skin breathe. Also - switch from everything you are using that isn't as natural as possible to natural/organic. Wipes, detergents, lotions, cleansers, etc, etc. Aveeno is good - but it still has a number of chemicals in them - even for sensitive skin. Avoid anything and everything with fragrance in it or alcohol. As far as the rest - I'd follow your others responses b/c I don't know too much about neverending diaper rash but I hope he feels better soon!