Hello,
You can't use this card out of France : it can be used only in the restricted net of "la Banque Postale" (i.e. the french Post Office) : It would have been better to keep this card at home in France.
If Kim wish me to send the money of his pension, the best way is to make a transfer directly from my bank account to Kim's bank account, by mean of your official "IBAN" (International Bank Account Number), with the mention of your exact address (a few years ago, I tried to make such a transfer but it was refused by the bank because the address was not correct.
I think that your father could give an "attorney power" (= an authorization) to your mother, regarding the withdrawal of money.
I hope that his health will improve very soon.