It sounds like your friend has a deeper issue and her mother probably did, too. It is probably not really about money at all. Fear of letting go, fear of emotional loss, all sorts of reasons that are tied to a deeper fear. Eg fear of poverty. Perhaps the mother or the mother’s parents were poor. Or could be some fear unrelated to money but that’s how the fear manifests.

As for what to do about her showing up with clothes, you ask what your readers would do. I would say “Do not bring me one more item. I do not want or need it.” (Pretty it up to suit your style but be firm and do not say “I’m sorry, but…”).

You’ve been friends a long time. If she values your friendship and respects you, she won’t mind you being firm and clear about not bringing anything more to you.

If she doesn’t, then perhaps it’s time to move on.

Thanks for sharing this. Your friend has emotional issues that are not your problem. You can’t fix this.