Today I finally called the benefits office to find out what exactly I need to do. After 25 minutes on the phone talking to two people, I learned that the FSA only covers premiums for Medicare Part D, and that amount is on Jack's Social Security 1099. (If I'd read the reminder more closely, I'd have known that, but who reads every word on a form letter.) Filing a claim is easy.
I'm rather glad Jack isn't here because it would have been really hard not to say "see how easy this was? how much money did you give back to McGraw-Hill because you are so bureaucracy-resistant?" At least it's one more thing I can cross off my to-do list and remove from my mind.