I'm glad you got a second opinion from someone with some sense. I agree to burn the old coop, and don't be around the smoke while your honey does that--you don't need to inhale any spores, etc.
I had a stem cell transplant in Feb and am still on immune suppressants. At first, the docs told me no chickens until 6 months post transplant---
. I also lasted about 3 weeks before I was in the coop. I always wear a mask when I'm inside my coop. My coop is a large walk-in affair and Honey added some more ventilation for me.
When we built new pens, we used an open concept. Our weather here is overall pretty temperate. Down to just above 0 in the winter, low triple digits in summer. I don't feel my birds need an enclosed space for the elements, just protection from predators. We went with cattle panels in a hoop style covered with a tarp. It's in a sheltered area so it's protected from a lot of wind, etc. this keeps airflow moving and disperses the dander, etc that builds up in an enclosed coop. Here are some pics, not the greatest but you kind of get the idea.....
https://www.backyardchickens.com/t/1003092/my-breeding-pens