I disagree that any decision making power was taken from her.

She was given instructions from a her doctors: get vaccinated if you want a transplant.

She chose to not follow those instructions.

I think her failing was, was that the disinformation she'd internalised some how made her think that the imagined risks of the vaccine were worse than guaranteed death from not getting a transplant.

I suspect she'd had a privileged enough life that the consequences of her making poor decisions like that were minimised: right up until the consequence was significant: death. Even then she failed to make a rational decision.