Your DH is a dear, for sure!
Brainstorming ideas:
Half-way up louver doors, stained to match beautiful molding.
They'll fold back to give easy access to fabric, when closed they'll protect your fabric while letting it breathe.
HOWEVER, sewing rooms are dust/lint havens and the doors will show a lot of dust on the louver parts.
The idea of a curtain/drape will protect, yet let your fabric breathe. Two panels so you can draw each panel to the side. What kind of a rod to use will have to be researched.