Following up on my post from Monday:
adrian_turtle talked to a different advisor (also with SHINE, like the person we talked to Monday).
He told her that "CommonHealth" is a Medigap plan, which you can only enroll in if you are under 65 and on Medicare because you're disabled. They don't require you to have less than X amount of money or income, but the premiums are based on a percentage of your income, and for us would be significantly less than a standard Medigap plan. He urged her to apply by printing the form and sending it in with a cover letter saying that this is a CommonHealth application, because otherwise they might treat it as a MassHealth application, which is not what we'd be looking for.
Edited to add: the only part of this information that's relevant for me right now is the "special election period"--because I inherited money this year, while I could enroll in CommonHealth, it wouldn't save money and might cost more than a standard Medigap policy. I have made a calendar entry to check in one year, and in two years, to see if it makes sense then.
Standard Medicare Open Enrollment ends on Dec. 7th, making this seem urgent--especially if we want to trust it to the post office--but I remembered that the letter saying my current Medicare Advantage plan won't be offered next year said I therefore have more time to choose a new plan.
So, I opened a chat window at Medicare.gov, and ran into a weird bit of terminology. Open enrollment ends on Dec. 7th, but I have a "special election period" from Dec. 8 to the end of February. The agent wanted to make clear that if I don't choose a plan by Dec. 31st, I wouldn't have Part D drug coverage or a Medicare Advantage plan.
I then asked if the special election period also applied to Medigap, and they told me that Medigap doesn't have annual open enrollment, if you don't buy it within six months after starting on Medicare the private insurance companies don't have to sell it to you. At that point, I thanked him and said that Massachusetts has different rules, and I think I need to talk to someone from the state.