Hi
@Lottie01
I think the time has come or v soon will when the card should be taken away, or the three digit security number on card back should be scratched off.
Friend's OH used to go online an order many thing often in multiples for money they couldn't afford, so she, when he was asleep scratched off the security number. She went on to his credit card co, to get money back on the basis that he no longer had capacity to make legal contracts. One has to be careful though, as just because someone make foolish money decisions, doesn't always mean that have lost capacity.
I think not realising the consequences of a multiple purchase, or the effect of amount spent, is evidence that a PWD is no longer capable of properly dealing with money.
I took away my OH's cr card. She asked where's it gone? Have I lost it? etc - she asked a fews times for a few days, but then forgot all about it and it was never mentioned again.
Thus, a matter judgment, for your mum, although you obviously have a view too.
Best wishes