I probably would have 'escorted' well followed her to the gas station, had her put in 20 dollars worth of gas, then got her to try her credit card, only if it was then refused would i pay it and wish her a good day. if she really was stranded she would have had no problem going along with this.

you were probably played as this is one of the oldest tricks in the book, and who on earth knows where the charities are in a state they are just passing through, let alone have the thought to go to them when you have just been told your mum has just had a heart attack! That said though i would like to think if i were stranded someone would help me.