Chicken dying from mites- what to do?

We've had a Silkie rooster for almost 9 years now and recently he's not been feeling well. We found out that he's covered in mites but we have no idea how to treat this. While we do have a few chickens outside, he has always lived in the house and only gone outside for small periods when he wants to. This unfortunately means that we have mites in the house which will we have to address but right now we're more concerned about losing our boy. He just stands around all day sleeping, is very light, and has been having trouble with his balance. We tried using DE for a time until my mother had a bad asthma attack so that's no longer an option. What can we do to help him recover while we tackle the larger problem?