I agree with your boyfriend. You can use eco-earth in a more dry state to reduce the respiratory issue, or use a dry bedding like sani-chips or aspen and add a humidity chamber around shedding times.
I like any of the reptile mulches, barks, or sphagnum/peat mixtures for the red-tails... just wach for mites int he barks, and don't let it get TOO moist!
And it goes without saying (but I will anyway

)... don't feed on a particle substrate!