Look through the cars paperwork, she may have written it down.
If the car was bought second-hand try asking the previous owner.
They factory setting for cars after ( I think ) 1994 was 1111, a lot of owners never bothered to change it.
Have a look at the keypad, if it has been used a lot the buttons will be worn, if only the number 1 is worn, give it a go.
herne, February 2010