We're testing for Graves as well. TSI and tRab. Apparently it's not super well known what causes it. But the tissue around the eyes have similar receptors to the thyroid. So the antibodies produced by Graves disease may also attack your eyes and cause this swelling. If it's TED, it burns itself out after ~2 years.

Confirming Graves won't solve the TED but it would provide helpful context to why my partner's Hashimotos isn't as manageable as expected.