If your roommate gives you permission to use their ATM bank card, can they later bring charges against you?
Question Details: He is an alcoholic, I've completely cared for him every day and night for a year and a half.
There's the legal answer and the practical answer.
Legally, if you had permission to use the ATM card, then so long as you did not violate the terms of the permission, you did not commit a crime. That means, for example, that if you were told you could use it to buy food for the house and pay household bills, you could take money out legally for those purposes--but if you took out money to buy yourself a TV, or jewlery, or take a vacation, etc. you would have exceeded your permission and may have committed a criminal act, since you had no permission to take out money for those purposes.
Practically, if there is nothing in writing showing you had permission and he now is claiming you did not, he can try to press charges and what will happen will depend on whether he is credible or believable--that is, do the authorities believe him when he says you did not have (or exceeded) permission, or will they believe you? Remember, the police and prosecutor do not know what "really" happened: all they know is what the witnesses (i.e. him and you) tell them, and they have to decide, based on what they told, who is more believable, and any relevant surrounding facts, whether a crime was committed or not.