Just because the battery drained while sitting for almost 2 months, doesn't mean she needs a new battery. I know Auto Zone will check, for free, the battery strength and whether the alternator is functioning. There will also be a date (probably on the side, either a sticker or etched into the plastic) on the battery that tells you the month and year the battery was manufactured. If its over 5 years old, you might want a new battery.
Did she get it jump started? If yes, the first thing would be to drive it around for a while, maybe an hour, to let the battery recharge from the alternator. Letting it sit with the engine idling won't make the alternator spin fast enough to create enough voltage to charge the battery, hence driving it.