Cliff Notes: FI's pellet stove (which I am extremely allergic to) stopped working, and he had to write his landlord a letter to get something done about it.
Follow up: FI's landlord agreed to put a new heat source in the house! They installed an ETS heater (electric heat that runs during off peak hours) last week. It keeps the place much warmer, and they also are working to make the house better insulated. It's made a HUGE difference in temperature, and I'm no longer totally sick after spending time there. We're still hoping to save enough money to build our own house in a few years, but in the meantime it's nice to be warm and not have the house filled with smoke.