
Hi there,
it sounds a lot to me like the boy crying wolf, after he had made up the story a couple of times, the villagers stopped believing him, one day he cried wolf for real, and no one came!!
It is difficult knowing when someone who appears to be always ill, is really genuinely ill or not.
it is probably worrying for her to, as you stated she thought it was an infection, and it wasn't.
May be you feel she is trying to bribe her mom in some way by making her feel worse by saying she will have to continue having treatment even after chemo
Just be there to support your friend, and the truth will come out. Lets hope that by delaying treatment it hasn't made things worse in the long run.
I wish you all the best.
Fairy-lights