AOC nailed it.

[George II]

85. Reread the tweet in the OP, please.

The original premise of the (2-year old) tweet is "insurance companies are recommending GoFundMe as official policy".

1. The letter was from the medical provider, not an insurance company
2. Nowhere was GoFundMe mentioned in the letter, nor it is "official policy"
3. There were no insurance companies involved whatsoever, the woman is a Medicare patient

Finally, as stated before:

4. The letter states that she was (temporarily) denied not because she couldn't afford the surgery itself (Medicare pays for that) but because she needed a "more secure" (not non-existent) financial plan for immunosuppressive medication coverage

Incidentally, the woman has had her initial surgery and is recovering satisfactorily, awaiting availability of a suitable heart donor.