She does not have authority to use the debit card and should not use it for these purposes. A power of attorney is not effective after death so this would not help her anyway. If there is a probate estate your friend can make a claim for reimbursement possibly.
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Your girl friend was an employee. She is NOTa relative.
As an employee, she is overstepping her authority.
She should do anything!
The family needs to make funeral decisions.
She might want to call me. I charge $2 a minute to talk. I think she needs to call me tomorrow morning.
713-847-6000 or email me at email@example.com
She should NOT be doing anything!
He is dead - he cannot give her permission to use his bank account anymore. Any authority she had, ended when he died.
She needs to call his attorney immediately and contact the executor of his estate (the person listed in his will.)
The family needs to handle his affairs - not an employee.
She might REALLY want to call me tomorrow.