The government knows that this is a common state for people, and would allow her to pay her estimated tax credit monthly directly to the insurance company.

So that isn't it. Any other guesses?

https://www.irs.gov/affordable-care-act/individuals-and-fami...

You and I are capable of finding, reading and understanding that document. I don't know if it is realistic to expect that from someone who spends all of their time and energy on mere subsistence.